Oral care compositions containing gel networks and fused silica

ABSTRACT

An oral care composition comprising a fused silica abrasive and a gel network.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/117,856, filed Nov. 25, 2008, the entire substance of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to oral compositions comprised of fusedsilica and gel networks. Also disclosed are methods for cleaning andpolishing teeth using these fused silica compositions.

BACKGROUND OF THE INVENTION

An effective oral composition can maintain and preserve tooth appearanceby removing dental stains and polishing the teeth. It may clean andremove external debris as well, which can aid the prevention of toothdecay and promote gingival health.

Abrasives in oral compositions aid in the removal of the tightlyadherent pellicle film to which dental stains affix. Pellicle filmusually comprises a thin acellular, glycoprotein-mucoprotein coating,which adheres to the enamel within minutes after teeth are cleaned. Thepresence of various food pigments lodged within the film accounts formost instances of teeth discoloration. An abrasive may remove thepellicle film with minimal abrasive damage to oral tissue, such as thedentin and enamel.

In addition to cleaning, it may be desirable for abrasive systems toprovide polishing of tooth surfaces, as polished surfaces may be moreresistant to ectopic deposition of undesirable components. Toothappearance may be improved by imparting a polished character to theteeth, because the surface roughness, that is, its polish, affects lightreflectance and scattering, which integrally relate to the teeth'svisual appearance. The surface roughness also affects tooth feel. Forexample, polished teeth have a clean, smooth, and slick feel.

Numerous dentifrice compositions use precipitated silicas as abrasives.Precipitated silicas are noted and described in U.S. Pat. No. 4,340,583,Jul. 20, 1982, to Wason, EP Patent 535,943A1, Apr. 7, 1993, to McKeownet al., PCT Application WO 92/02454, Feb. 20, 1992 to McKeown et al.,U.S. Pat. No. 5,603,920, Feb. 18, 1997, and U.S. Pat. No. 5,716,601,Feb. 10, 1998, both to Rice, and U.S. Pat. No. 6,740,311, May 25, 2004to White et al.

While providing effective cleaning of teeth, precipitated silicas inoral compositions may present compatibility problems with key formulaactives, such as fluoride and cationic antibacterials. Thesecompatibility problems have been shown to be directly related to surfaceproperties of precipitated silicas such as surface area, number ofhydroxyl groups, and porosity. Additionally, some thickeners orstructuring systems are not compatible with formulation actives, such ashydrogen peroxide.

A need exists for an abrasive system and structuring system that hasgood compatibility with oral care actives and key dentifrice components.A need also exists for a structuring system which can suspend theabrasive to enable the abrasive to participate in the cleaning. Thefused silicas and gel networks of the present invention may provide oneor more of these advantages.

The present invention therefore relates to oral compositions and methodsusing such oral compositions that may provide one or more of thesebenefits.

SUMMARY OF THE INVENTION

The present invention relates to oral care compositions comprising afused silica abrasive and a gel network. The present invention furtherrelates to methods for cleaning and polishing dental enamel using thesefused silica and gel network compositions. In some embodiments, the gelnetwork is used to structure or thicken the oral care composition. Thegel network may be formed by one or more fatty amphiphiles such as cetylalcohol and stearyl alcohol. The oral care composition may beessentially free of polymeric thickeners or it may contain polymericthickeners to aid in structuring the oral care composition.

In one embodiment, the oral care composition may comprise fused silicaas an abrasive, gel networks as a structuring agent, hydrogen peroxide,and a fluoride source. The fluoride source may be stannous fluoride orsodium fluoride. The oral care composition may also comprise a mono ordi alkyl phosphate as a chelant or tooth substantive agent. The oralcomposition may also comprise one or more essential oils asantibacterial agents or flavoring materials. In another embodiment, theoral care composition may comprise fused silica as an abrasive, gelnetworks as a structuring agent, and a stannous source.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a table of material properties of various fused andprecipitated silicas.

FIG. 2 is a table of compatibility data for fused and precipitatedsilicas.

FIG. 3A is a table of sodium fluoride-based formulations of oral carecompositions.

FIG. 3B is a table of PCR and RDA values for FIG. 3A compositions.

FIG. 4A is a table of stannous fluoride-based formulas of oral carecompositions.

FIG. 4B is a table of PCR and RDA values for FIG. 4A compositions.

FIG. 5 is a table of cleaning and abrasivity of fused silica.

FIGS. 6A A-I are SEM micrographs of precipitated and fused silicaimages.

FIG. 7A is a table of composition formulas.

FIG. 7B is a table of stannous, zinc, and fluoride compatibility forFIG. 7A compositions.

FIG. 8 is a table of stannous compatibility as a function of silicaload.

FIG. 9A is a table of formula compositions comprising peroxide and fusedand precipitated silicas.

FIG. 9B is a table of peroxide compatibility for the FIG. 9Acompositions.

FIG. 10A is a table of formula compositions comprising fused silica.

FIG. 10B is a table of cleaning and whitening performance for FIG. 10Acompositions.

FIG. 11A is table of formula compositions containing fused andprecipitated silicas.

FIG. 11B is a table of consumer perception data for FIG. 11Acompositions.

FIG. 12 is a depiction if how FIG. 12A and 12B fit together into asingle table.

FIG. 12A is a first portion of a table of additional formula examples.

FIG. 12B is a second portion of a table of additional formula examples.

FIG. 13A is a table of formula examples.

FIG. 13B is a table of PCR and RDA values for FIG. 13A sodium fluoridebased compositions.

FIG. 13C is a table of formula examples.

FIG. 13D is a table of RDA values for FIG. 13C stannous fluoride basedcompositions.

DETAILED DESCRIPTION OF THE INVENTION

While the specification concludes with claims that particularly pointout and distinctly claim the invention, it is believed the presentinvention will be better understood from the following description.

DEFINITIONS

The term “orally acceptable carrier” as used herein means a suitablevehicle or ingredient, which can be used to form and/or apply thepresent compositions to the oral cavity in a safe and effective manner.Such vehicle may include materials such as fluoride ion sources,antibacterial agents, anticalculus agents, buffers, other abrasivematerials, peroxide sources, alkali metal bicarbonate salts, thickeningmaterials, humectants, water, surfactants, titanium dioxide, flavorsystem, sweetening agents, cooling agents, xylitol, coloring agents,other suitable materials, and mixtures thereof.

The term “comprising” as used herein means that steps and ingredientsother than those specifically mentioned can be added. This termencompasses the terms “consisting of” and “consisting essentially of.”The compositions of the present invention can comprise, consist of, andconsist essentially of the essential elements and limitations of theinvention described herein, as well as any of the additional or optionalingredients, components, steps, or limitations described herein.

The term “effective amount” as used herein means an amount of a compoundor composition sufficient to induce a positive benefit, an oral healthbenefit, and/or an amount low enough to avoid serious side effects,i.e., to provide a reasonable benefit to risk ratio, within the soundjudgment of a skilled artisan.

The term “oral composition” as used herein means a product that in theordinary course of usage is retained in the oral cavity for a timesufficient to contact some or all of the dental surfaces and/or oraltissues for purposes of oral activity. The oral composition of thepresent invention may be in various forms including toothpaste,dentifrice, tooth gel, tooth powders, tablets, rinse, subgingival gel,foam, mouse, chewing gum, lipstick, sponge, floss, prophy paste,petrolatum gel, or denture product. The oral composition may also beincorporated onto strips or films for direct application or attachmentto oral surfaces, or incorporated into floss.

The term “dentifrice” as used herein means paste, gel, powder, tablets,or liquid formulations, unless otherwise specified, that are used toclean the surfaces of the oral cavity.

The term “teeth” as used herein refers to natural teeth as well asartificial teeth or dental prosthesis.

The term “polymer” as used herein shall include materials whether madeby polymerization of one type of monomer or made by two (i.e.,copolymers) or more types of monomers.

The term “water soluble” as used herein means that the material issoluble in water in the present composition. In general, the materialshould be soluble at 25° C. at a concentration of 0.1% by weight of thewater solvent, preferably at 1%, more preferably at 5%, more preferablyat 15%.

The term “phase” as used herein means a mechanically separate,homogeneous part of a heterogeneous system.

The term “substantially non-hydrated” as used herein means that thematerial has a low number of surface hydroxyl groups or is substantiallyfree of surface hydroxyl groups. It may also mean that the materialcontains less than about 5% total water (free or/and bound).

The term “majority” as used herein means a number larger than half thetotal.

All percentages, parts and ratios are based upon the total weight of thecompositions of the present invention, unless otherwise specified. Allsuch weights as they pertain to listed ingredients are based on theactive level and, therefore, do not include solvents or by-products thatmay be included in commercially available materials, unless otherwisespecified. The term “weight percent” may be denoted as “wt. %” herein.

All molecular weights as used herein are weight average molecularweights expressed as grams/mole, unless otherwise specified.

Fused Silica

Fused silica is a high-purity amorphous silicon dioxide. It is sometimesreferred to as fused quartz, vitreous silica, silica glass, or quartzglass. Fused silica is a type of glass, which, typical of glasses, lackslong-range order in its atomic structure. But the optical and thermalproperties of fused silica are unique from those of other glasses, asfused silica typically has more strength, thermal stability, andultraviolet transparency. For these reasons, fused silica is known to beused in situations such as semiconductor fabrication and laboratoryequipment.

The present invention utilizes fused silica in oral compositions,particularly in dentifrice compositions. While many current dentifricecompositions use silica as a thickening agent as well as an abrasive,the silicas typically used are precipitated silicas. Precipitatedsilicas are made by an aqueous precipitation or drying process. Incontrast, fused silica is typically produced by melting high puritysilica sand at very high temperatures, around 2000° C.

FIG. 1 is a table of material properties of various types of fusedsilica. For comparison, the same physical properties for someprecipitated silicas are also shown. Some of the key material propertiesthat distinguish fused silica from precipitated silica are shown,including BET surface area, loss on drying, loss on ignition, silanoldensity, bulk density, tapped density, oil absorption, and particle sizedistribution. Each of these material properties is discussed in moredetail below.

The process of heating the silica to such high temperatures destroys theporosity and surface functionality of the silica. It produces a silicathat is extremely hard and inert to most substances. The melting processalso results in a low BET surface area, lower than that of precipitatedsilica. The BET surface area of fused silica ranges from about 1 m²/g toabout 50 m²/g, from about 2 m²/g to about 20 m²/g, from about 2 m²/g toabout 9 m²/g, and from about 2 m²/g to about 5 m²/g. By comparison,precipitated silicas typically have a BET surface areas ranging between30 m²/g and 80 m²/g. BET surface area is determined by BET nitrogenabsorption method of Brunaur et al., J. Am. Chem. Soc., 60, 309 (1938).See also U.S. Pat. No. 7,255,852, issued Aug. 14, 2007 to Gallis.

Fused silica, relative to other types of silica, typically has a lowamount of free or/and bound water. The amount of bound and free water infused silica is typically less than about 10%. The amount of bound andfree water in fused silica may be less than about 5%, or less than about3%. Silicas with less than about 5% bound and free water may beconsidered substantially non-hydrated. The total bound and free watercan be calculated by totaling two measurements, loss on drying (LOD) andloss on ignition (LOI). For loss on drying, performed first, a samplemay be dried at 105° C. for two hours, the weight loss being the freewater. For loss on ignition, the dried sample then may be heated for onehour at 1000° C., the weight loss being the bound water. The sum of theLOD and LOI represents the total bound and free water in the originalsample. For example, following the described test method, fused silicaTECO SIL 44CSS has a loss on drying of 0.1%, and a loss on ignition of2.2%, for a sum of 2.3% total water. In comparison, a typicalprecipitated silica, Z-119, has a loss on drying of 6.1% and a loss onignition of 5.1%, for a sum of 11.2% total water. (For another testmethod, see the United States Pharmacopeia-National Formulary (USP-NF),General Chapter 731, Loss on Drying and USP-NF, General Chapter 733,Loss on Ignition.)

Fused silica, relative to precipitated silica, has a low number ofsurface hydroxyl or silanol groups. The accounting of surface hydroxylgroups can be found by using nuclear magnetic resonance spectroscopy(nmr) to measure the silanol density of a particular silica. Silanolsare compounds containing silicon atoms to which hydroxy substituentsbond directly. When a solids nmr analysis is performed on varioussilicas, the silicon signal is enhanced by energy transfer fromneighboring protons. The amount of signal enhancement depends on thesilicon atom's proximity to protons found in the hydroxyl groups locatedat or near the surface. Therefore, the silanol density, stated asnormalized silanol signal intensity (intensity/g), is a measure ofsurface hydroxyl concentration. The silanol density for fused silicasmay be less than about 3000 intensity/g, in some embodiments less thanabout 2000 intensity/g, and commonly less than about 900 intensity/g.Fused silicas may contain an intensity/g of from about 10 to about 800and typically from about 300 to about 700. For example, a sample offused silica TECO SIL 44CSS has a silanol density of 574 intensity/g. Atypical precipitated silica measures above 3000 intensity/g andtypically above 3500 intensity/g. For example, Huber's Z-119 measures3716 intensity/g. Test method for silanol density uses solid state nmrwith cross polarization with magic angle spinning (5 kHz) and high powergated proton decoupling and VARIAN UNITY PLUS 200 spectrometer with a 7mm p made by Doty Scientific. The relaxation delay is 4 s and thecontact time is 3 ms. Number of scans is between 8,000 and 14,000.Samples are weighed to 0.1 mg for normalization procedure. Silanoldensity is measured by plotting and integrating spectra in absoluteintensity mode.

The surface reactivity of silica, a reflection of the relative number ofsurface hydroxyls, may be measured by a silica's ability to absorbmethyl red from a solution. This measures the relative number ofsilanols. The test is based on the fact that methyl red will selectivelyabsorb on the reactive silanol sites of a silica surface. In someembodiments, the methyl red solution after exposure to fused silica mayhave an absorbance greater than the absorbance of a solution exposed toa typical precipitated silica. This is because the fused silica does notreact as much with the methyl red solution as the precipitated silica.Typically, the fused silica will have a methyl red solution absorbanceof 10% greater than a standard precipitated silica because theprecipitated silica reacts more readily with the methyl red solution.The absorbance may be measured at 470 nm. Ten grams of 0.001% methyl redin benzene is added to 0.1 gram each of two silica samples and mixed forfive minutes on a magnetic stirrer. The resulting slurries arecentrifuged for five minutes at 12,000 rpms, and then the percenttransmission at 470 nm is determined for each sample and averaged. See“Improving the Cationic Compatibility of Silica Abrasives Through theUse of Topochemical Reactions” by Gary Kelm, Nov. 1, 1974, in Iler,Ralph K., The Colloid Chemistry of Silica and Silicates, CornellUniversity Press, Ithaca, N.Y., 1955.

Without being bound by theory, it is believed that the fused silica,with its low BET specific surface area, low porosity, and low number ofsurface hydroxyl groups, is less reactive than precipitated silica.Consequently, the fused silica may adsorb less of other components, suchas flavors, actives, or cations, leading to better availability forthese other components. For example, dentifrices incorporating fusedsilica have superior stability and bioavailability for stannous,fluoride, zinc, other cationic antibacterials, and hydrogen peroxide.Fused silica formulated in a dentifrice composition may result in atleast about 50%, 60%, 70%, 80%, or 90% compatibility with cations orother components. In some embodiments, the cation may be stannous.

In FIG. 2, the stannous and fluoride compatibility of various types offused and precipitated silicas is shown. Stannous and fluoridecompatibility was determined by adding 15% of silica into asorbitol/water mixture containing 0.6% sodium gluconate and 0.454%stannous fluoride and mixed well. Each silica slurry sample was thenplaced on stability at 40° C. for 14 days, and then analyzed forstannous and fluoride. A measure of the concentration of solublestannous and soluble zinc under normal tooth brushing conditions may beas follows: Prepare a 3:1 water to dentifrice (silica) slurry andcentrifuge it to isolate a clear layer of supernatant. Dilute thesupernatant in acid solution (nitric or hydrochloric acid) and analyzeby inductively coupled plasma optical emission spectrometry. Percentcompatibility is calculated by deducting the analyzed from initialvalues. A measure of the concentration of soluble fluoride under normaltooth brushing conditions may be as follows: Prepare a 3:1 water todentifrice (silica) slurry and centrifuge it to isolate a clear layer ofsupernatant. The supernatant is analyzed for fluoride by either fluorideelectrode (after mixing 1:1 with a TISAB buffer) or diluted withhydroxide solution and analyzed by ion chromatography with conductivitydetection. Percent compatibility is calculated by deducting the analyzedfrom initial values. In general, cation compatibility may be determinedby the “% CPC compatibility test” disclosed in U.S. Pat. No. 7,255,852.

There are numerous other characteristic differences between fused silicaand precipitated silicas besides compatibility and concentration ofsurface hydroxyls. For example, fused silica is denser and less porous.The bulk density of fused silica is typically higher than 0.45 g/ml, andmay be from about 0.45 g/ml to about 0.80 g/ml, while the bulk densityof precipitated silicas is at most about 0.40 g/ml. The tapped densityof fused silica is typically higher than 0.6 g/ml, and may be from about0.8 g/ml to about 1.30 g/ml, while the tapped density of precipitatedsilicas is at most 0.55 g/ml. Bulk density and tapped density can bemeasured by following the methods in the USP-NF, General Chapter 616,Bulk Density and Tapped Density. For bulk density, method 1, Measurementin a Graduated Cylinder may be used; for tapped density, method 2, whichuses a mechanical tapper, may be followed. Bulk density and tappeddensity represent mass to volume ratios of particles (multiple particlesconfined in a given space), and reflect trapped air, porosity, and howparticles fit together in a given space. A true or intrinsic density ofa particle (mass to volume ratio of a single particle) for fused silicais from about 2.1 g/cm³ to 2.2 g/cm³, while the true or intrinsicdensity of precipitated silicas is at most about 2.0 g/cm³. Similarly,fused silica's specific gravity may be from about 2.1 to 2.2, while thespecific gravity of precipitated silicas may be at most about 2.0. Thedifference in density may have a significant effect during themanufacture of a dentifrice product, for example, where fused silica'shigher density reduces or removes the processing step of deaeration,which may result in shorter batch cycle times.

Fused silica has comparatively low water and oil absorption,measurements that correlate well with BET specific surface area. Waterabsorption for fused silica, meaning the amount of water that it canabsorb while maintaining a powder consistency, is less than about 80g/100 g, optionally less than about 70 g/100 g, about 60 g/100 g, orabout 50 g/100 g. The water absorption for fused silica can be evenlower, in the range of less than about 40 g/100 g, optionally less thanabout 30 g/100 g, and may be from about 2 g/100 g to about 30 g/100 g.For precipitated silicas, water absorption is typically about 90 g/100g. Water absorption is measured using the J.M Huber Corp. standardevaluation method, S.E.M No. 5,140, Aug. 10, 2004). Oil absorption forfused silica is less than about 75 ml dibutyl phthalate/100 g fusedsilica, and may be less than about 60 ml dibutyl phthalate/100 g fusedsilica. Oil absorption may range from about 10 ml dibutyl phthalate/100g fused silica to about 50 ml dibutyl phthalate/100 g fused silica, andit may be desired to be from about 15 ml dibutyl phthalate/100 g fusedsilica to about 45 ml dibutyl phthalate/100 g fused silica. Forprecipitated silicas, oil absorption is typically about 100 ml dibutylphthalate/100 g precipitated silica. (Oil absorption is measuredaccording to the method described in U.S. Patent Application2007/0001037A1, published Jan. 4, 2007.

Due to its relatively low water absorption, the fused silica may be madeinto a slurry, ultimately allowing quicker processing and faster batchtimes. In general, to create a precipitated silica slurry wouldtypically require at least about 50% water. Therefore, it would not bepractical to use a precipitated silica slurry in the manufacture of oralcompositions. But because of the inertness, or lack of porosity of fusedsilica, reflected in fused silica's relatively low water absorption,fused silica slurries can be made in which water comprises less thanabout 30% in some embodiments, or less than 40% in some embodiments.Some embodiments of the present invention may be a method of making anoral care composition comprising the addition of a fused silica slurry.In some embodiments, the fused silica slurry comprises a binder. Thismay help keep the fused silica suspended in the slurry, especially ifthere is a high water amount. It may also allow the binder more time tohydrate. In some embodiments, the fused silica slurry may contain a gelnetwork. In some embodiments, the binder is selected from the groupconsisting of carboxyvinyl polymers, carrageenan, hydroxyethylcellulose, water soluble salts of cellulose ethers such as sodiumcarboxymethylcellulose, cross-linked carboxymethylcellulose, sodiumhydroxyethyl cellulose, cross-linked starch, natural gums such as gumkaraya, xanthan gum, gum arabic, and gum tragacanth, magnesium aluminumsilicate, silica, alkylated polyacrylates, alkylated cross linkedpolyacrylates, and mixtures thereof. The fused silica slurry may bepremixed. In some embodiments, the fused silica slurry may be flowableor pumpable. In some embodiments, the fused silica slurry may furthercomprise a preservative, for example benzoic acid, sodium benzoate,sorbic acid or parabens may be used, at less than about 1%.

Fused silica typically has much less conductivity than precipitatedsilica. Conductivity is an indirect measure of dissolved electrolytes,and precipitated silica can not be made without producing solubleelectrolytes. So while precipitated silica ranges from about 900-1600micro siemens/cm (based on 5% dispersion in deionized water), fusedsilica measures less than about 10 micro Siemens/cm (measurements madeusing an Orion 3 Star Benchtop Conductivity Meter available from ThermoElectron Corporation).

The pH of fused silica may range from about 5 to about 8, while the pHof precipitated silicas is typically from about 7 to about 8. pH isdetermined according to U.S. patent application 2007/0001037A1,published Jan. 4, 2007.

The refractive index, a measure of light transmission, is typicallyhigher for fused silica than it is for precipitated silica. Put in asorbitol/water mixture, fused silica measures a refractive index of atleast about 1.45, while precipitated silicas measures from 1.44 to1.448. A higher refractive index may allow the making of clear gelseasier. Refractive index is determined using the method disclosed inU.S. patent application 2006/0110307A1, published May 25, 2006.

Fused silica typically has a Mohs hardness greater than about 6, greaterthan about 6.5, and greater than about 7. Precipitated silicas are notas hard, typically having a Mohs hardness of 5.5-6.

Another distinction between fused and precipitated silica is purity,with fused silica having a higher purity than precipitated. The percentof silica, by weight, in fused silica may be greater than about 97%,about 97.5%, about 98%, about 98.5%, in some embodiments greater thanabout 99%, and in some embodiments greater than about 99.5%. Forprecipitated silica, the percent of silica, by weight, is typically onlyabout 90%. These purity measurements include water as an impurity, andmay be calculated using the LOD and LOI methods described previously.

Depending on the supplier, impurities other than water may include metalions and salts, among other materials. In general, for precipitatedsilicas, impurities other than water are mostly sodium sulfate.Precipitated silicas will typically have from about 0.5% to 2.0% sodiumsulfate. Fused silica typically does not contain any sodium sulfate, orhas less than 0.4%. Purity levels that do not include water may bedetermined by referring to the USP-NF Dental Silica Silicon Monograph,as follows: Purity is the combined results of the Assay (silicondioxide) and Sodium sulfate tests. For Assay Transfer about 1 g ofSilica Gel to a tared platinum dish, ignite at 1000° C. for 1 hour, coolin a desiccator, and weigh. Carefully wet with water, and add about 10mL of hydrofluoric acid, in small increments. Evaporate on a steam bathto dryness, and cool. Add about 10 mL of hydrofluoric acid and about 0.5mL of sulfuric acid, and evaporate to dryness. Slowly increase thetemperature until all of the acids have been volatilized, and ignite at1000° C. Cool in a desiccator, and weigh. The difference between thefinal weight and the weight of the initially ignited portion representsthe weight of SiO2. Sodium sulfate—Transfer about 1 g of Dental-TypeSilica, accurately weighed, to a platinum dish, wet with a few drops ofwater, add 15 mL of perchloric acid, and place the dish on a hot plate.Add 10 mL of hydrofluoric acid. Heat until copious fumes are evolved.Add 5 mL of hydrofluoric acid, and again heat to copious fumes. Addabout 5 mL of boric acid solution (1 in 25), and heat to fumes. Cool,and transfer the residue to a 400-mL beaker with the aid of 10 mL ofhydrochloric acid. Adjust the volume with water to about 300 mL, andbring to boiling on a hot plate. Add 20 mL of hot barium chloride TS.Keep the beaker on the hot plate for 2 hours, maintaining the volumeabove 200 mL. After cooling, transfer the precipitate and solution to adried, tared 0.8-μm porosity filter crucible. Wash the filter andprecipitate 8 times with hot water, dry the crucible at 105° C. for 1hour, and weigh. The weight, multiplied by 0.6085, is the sodium sulfatecontent of the amount of specimen taken. Not more than 4.0% is found.Purity may also be determined through use of standard analyticaltechniques, such as atomic absorption spectroscopy or through elementalanalysis.

The unique surface morphology of fused silica may result in morefavorable PCR/RDA ratios. The Pellicle Cleaning Ratio (PCR) of the fusedsilica of the present invention, which is a measure of the cleaningcharacteristics of a dentifrice, ranges from about 70 to about 200 andpreferably from about 80 to about 200. The Radioactive Dentine Abrasion(RDA) of the inventive silica, which is a measure of the abrasiveness ofthe fused silica when incorporated into a dentifrice, is less than about250, and may range from about 100 to about 230.

FIG. 3( a) shows sodium fluoride-based formula compositions comprisingvarious fused and precipitated silicas. FIG. 3( b) shows thecorresponding PCR and RDA values. FIG. 4( a) shows stannousfluoride-based formula compositions comprising various fused andprecipitated silicas. FIG. 4( b) shows the corresponding PCR and RDAvalues. The PCR values are determined by the method discussed in “InVitro Removal of Stain with Dentifrice,” G. K. Stookey, et al., J.Dental Res., 61, 1236-9, 1982. The RDA values are determined accordingto the method set forth by Hefferren, Journal of Dental Research,July-August 1976, pp. 563-573, and described in Wason, U.S. Pat. Nos.4,340,583, 4,420,312, and 4,421,527. RDA values may also be determinedby the ADA recommended procedure for determination of dentifriceabrasivity. The PCR/RDA ratio of the fused silica, when incorporatedinto a dentifrice, may be greater than 1, indicating that the dentifriceis providing effective pellicle cleaning without too much abrasivity.The PCR/RDA ratio may also be at least about 0.5. The PCR/RDA ratio is afunction of the particle size, shape, texture, hardness, andconcentration.

FIG. 5 is a table of PCR and RDA data for various amounts of silica,both fused and precipitated. It demonstrates that fused silica (TS10 andTS44CSS) can have superior cleaning capability (PCR) in comparison toprecipitated silicas (Z119 and Z109). The data shows that an oralcomposition with 5% fused silica may clean better than an oralcomposition with 10% of precipitated silica. In addition, the datademonstrates that fused silica can provide this cleaning while stillbeing within acceptable abrasivity levels (RDA).

The shape of the particles of fused silica may be classified as eitherangular or spherical, or a combination of shapes, depending on the typeof manufacturing process. Additionally, the fused silica may also bemilled to reduce particle size. Spherical particles include any particlethat is rounded or elliptical in shape. Angular particles include anyparticle that is not spherical, including polyhedral shapes. The angularparticles may have rounded edges, sharp edges, jagged edges, or acombination. The particle shape of the fused silica can impact itsabrasivity. For example, at the same particle size, spherical fusedsilica may have a lower radioactive dentin abrasion (RDA) than that ofangular fused silica. Consequently, it may be possible to optimizecleaning capability while not increasing abrasivity. Or, as anotherexample, a prophy paste or a paste to be used weekly could comprise anangular fused silica with a large particle size.

Compositions that comprise spherical fused silica, that is, wherein atleast 25% of the fused silica particles are spherical, have certainadvantages. Due to the rounded edges, the spherical fused silica may beless abrasive. This means that the PCR to RDA ratio can be improvedwhile still providing good cleaning. Also, spherical fused silica may beused at higher levels without being too abrasive. The spherical fusedsilica may also be used in combination with the angular fused silica, orsilica wherein at least about 25% of the particles are angular. Thiscould help lower costs, while still delivering good cleaning withacceptable abrasivity. In embodiments that have both angular andspherical fused silica, the amount of angular fused silica may be fromabout 1% to about 10%, by weight of the composition. In some embodimentswherein at least 25% of the fused silica particles are spherical, theRDA may be less than 150, in other embodiments less than 120. In someembodiments, the PCR to RDA ratio may be at least about 0.7, at leastabout 0.8, at least about 0.9, or at least about 1.0. In someembodiments, the median particle size of the fused silica is from about3.0 microns to about 15.0 microns.

Examples of spherical fused silicas include SPHERON P1500 and SPHERON N2000R, made by Japanese Glass Company, and SUN SIL 130NP.

Importantly, fused silica particles generally do not form as manyaggregated clusters as precipitated silicas do and typically do not formaggregate clusters as easily as precipitated silicas do. In someembodiments, the majority of fused silica particles do not formaggregated clusters. In contrast, precipitated silicas generally formaggregated clusters of irregularly shaped submicron primary particles. Aprecipitated silica may be treated or coated which may increase ordecrease the amount of aggregation. The particle shape of both fused andprecipitated silica may be determined using a scanning electronmicroscope (SEM).

FIG. 6, (a)-(i), are SEM micrographs of precipitated and fused silicasat 3000× magnification. Samples were sputter coated with gold usingEMS575X Peltier cooled Sputter coater. SEM images of the sample surfacewere obtained using a JEOL JSM-6100. The SEM was operated at 20 kV, 14mm WD, and 1500× and 3000× magnification.

Micrographs (a) and (b), of precipitated silicas Z-109 and Z-119, showirregularly shaped-agglomerated particles. Particles appear to be madeof agglomerated smaller particles loosely packed together. Micrographs(c) and (d), which are fused silicas SPHERON P1500 and SPHERON N 2000R,show regularly shaped spheroid particles. That is, each particle, forthe most part, is shaped like a sphere. And micrographs (e), (f), (g),(h), and (i), which are fused silicas 325F, RG5, RST 2500 DSO, TECO-SIL44C, and TECO-SIL 44CSS, show irregularly shaped dense particles. Someparticles may be agglomerated, tightly packed, while others appear toconsist of a single mass. In general, this last set of fused silicas hasparticles that are irregularly shaped with defined and/or sharp edges,and could be considered angular.

In general, oral compositions, for example dentifrice, comprising fusedsilica may be distinguished from oral compositions comprising onlyprecipitated silica by heating both compositions to ash at about 500° C.and comparing the samples. Heating to about 500° C. leaves only theabrasive, but is not hot enough to drive off the hydroxyl groups. Thefused silica and precipitated silica may be distinguished via BETsurface area or SEM analysis, as described above, or by XRD (x-rayscattering technique) analysis.

The median particle size of fused silicas of the present invention mayrange from about 1 micron to about 20 microns, from about 1 micron toabout 15 microns, from about 2 microns to about 12 microns, from about 3microns to about 10 microns, as measured by Malvern Laser LightScattering Particle Sizing. Angular shaped particles may have a particlesize (median D50) from about 5 to about 10 microns. It is preferred thatthe D90 (average size of 90% of particles) is less than about 50microns, less than about 40 microns, less than about 30 microns, or lessthan about 25 microns. A low particle size of fused silica may give asensitivity benefit, as the particles may block tubule openings.Particle size is determined using the methods disclosed in U.S. patentapplication 2007/0001037A1, published Jan. 4, 2007.

The size of fused silica particles can be controlled by the processingof the material. Precipitated silica will have a size based on themethod of precipitation. While the particle size of some precipitatedsilicas overlap with those of fused silicas, typically precipitatedsilicas will have a bigger particle size. For example, precipitatedsilicas Z-109 and Z-119 range from about 6 microns to about 12 micronsand from about 6 microns to about 14 microns, respectively. But it isimportant to note that if, for example, a fused silica and aprecipitated silica have the same particle size, the fused silica's BETsurface area will typically still be much lower than the precipitatedsilica's BET surface area due to the lack of porosity of the fusedsilica particle. So a fused silica having a similar particle size tothat of a precipitated silica will be distinguishable from theprecipitated silica and offer the improved cleaning and/or compatibilityover the precipitated silica.

In some embodiments, the particle size of the fused silica may beoptimized for cleaning. In some embodiments, the median particle size ofthe fused silica may be from about 3 microns to about 15 microns,wherein 90% of the particles have a particle size of about 50 microns orless. In other embodiments, the median particle size may be from about 5microns to about 10 microns, wherein 90% of the particles have aparticle size of about 30 microns or less. In other embodiments, themedian particle size may be from about 5 microns to 10 microns, wherein90% of the particles have a particle size of about 15 microns or less.

The fact that fused silica is harder than precipitated silicacontributes to its ability to clean better. This means that fused silicaof the same particle size and in the same amount as a precipitatedsilica will comparatively clean better. For example, the PCR for a fusedsilica composition may be at least about 10% greater than the PCR for aprecipitated silica composition when the median particle size and silicalevels are the same.

Fused silica's better cleaning capability leads to different formulationpossibilities, some that maximize cleaning, some that improve cleaningwhile not increasing abrasivity, some that improve cleaning whiledecreasing abrasivity, or some formulations that are simply more costeffective because less abrasive is required to deliver acceptablecleaning. In some embodiments, an oral care composition comprising afused silica abrasive may have a PCR of at least about 80, at leastabout 100, or at least about 120. In some embodiments, the ratio of PCRto RDA may be at least about 0.6, at least about 0.7, at least about0.8, or at least about 0.9. In some embodiments, the composition maycomprise less than about 20% fused silica, by weight of the composition.In some embodiments, the composition may comprise less than about 15%fused silica, by weight of the composition, and have a PCR of at leastabout 100, or may comprise less than about 10% fused silica, by weightof the composition, and have a PCR of at least about 100.

In some embodiments optimized for improved cleaning, at least about 80%of the fused silica particles may be angular. In other embodiments, thecomposition may further comprise precipitated silica. In still otherembodiments, the composition may comprise a gel network. In someembodiments, the composition may comprise one or more of the following:anticaries agent, antierosion agent, antibacterial agent, anticalculusagent, antihypersensitivity agent, anti-inflammatory agent, antiplaqueagent, antigingivitis agent, antimalodor agent, and/or an antistainagent. In some embodiments, the composition may comprise an additionalabrasive material, including, but not limited to precipitated silica,calcium carbonate, dicalcium phosphate dihydrate, calcium phosphate,perlite, pumice, calcium pyrophosphate, nanodiamonds, surface treatedand de-hydrated precipitated silica, and mixtures thereof. Someembodiments may be a method of cleaning subject's teeth and oral cavityby using an oral care composition comprising a fused silica abrasive inan orally acceptable carrier, wherein the fused silica abrasive has amedian particle size from about 3 microns to about 15 microns, andwherein 90% of the particles have a particle size of about 50 microns orless.

In some embodiments, the particle size of the fused silica may bereduced to focus on polishing and anti-sensitivity benefits. In someembodiments, the fused silica may have a median particle size of fromabout 0.25 micron to about 5.0 microns, from about 2.0 microns to about4.0 microns, or from about 1.0 micron to about 2.5 microns. In someembodiments, 10% of the fused silica particles may have a particle sizeof about 2.0 microns or less. In some embodiments, 90% of the fusedsilica particles may have a particle size of about 4.0 microns or less.In some embodiments, particles may have a median particle size that isno greater than the average diameter of a mammalian dentin tubule, suchthat one or more particles is/are capable of becoming lodged within thetubule, thereby effecting a reduction or elimination of perceived toothsensitivity. Dentinal tubules are structures that span the entirethickness of dentin and form as a result of the mechanism of dentinformation. From the outer surface of the dentin to the area nearest thepulp, these tubules follow an S-shaped path. The diameter and density ofthe tubules are greatest near the pulp. Tapering from the inner to theoutermost surface, they have a diameter of 2.5 microns near the pulp,1.2 microns in the middle of the dentin, and 0.9 microns at thedentino-enamel junction. Their density is 59,000 to 76,000 per squaremillimeter near the pulp, whereas the density is only half as much nearthe enamel.

To enhance the anti-sensitivity benefit of a small particle size,compositions may further comprise additional anti-sensitivity agentssuch as, for example, tubule blocking agents and/or desensitivityagents. Tubule blocking agents may be selected from the group consistingof stannous ion source, strontium ion source, calcium ion source,phosphorus ion source, aluminum ion source, magnesium ion source, aminoacids, bioglasses, nanoparticulates, polycarboxylates, Gantrez, andmixtures thereof. The amino acids may be basic amino acids, and a basicamino acid may be arginine. Nanoparticulates may be selected from thegroup consisting of nanohydroxy apatite, nanotitanium dioxide, nanometal oxides, and mixtures thereof. The desensitivity agent may be apotassium salt selected from the group consisting of potassium fluoride,potassium citrate, potassium nitrate, potassium chloride, and mixturesthereof. Some embodiments may be a method of reducing hypersensitivityof the teeth by administering to a subject in need an oral carecomposition comprising a fused silica, wherein the fused silica has amedian particle size of 0.25 micron to about 5.0 microns. Someembodiments may be a method of polishing the teeth by administering to asubject an oral care composition comprising a fused silica, wherein thefused silica has a median particle size of 0.25 micron to about 5.0microns.

In other embodiments, the particle size may be relatively large to bepart of a prophy paste or some other non-daily use paste. In someembodiments, the fused silica may have a median particle size of atleast about 7 microns and wherein the composition has a PCR of at leastabout 100. In other embodiments, the median particle size may be fromabout 7 microns to about 20 microns. In some embodiments with the medianparticle size at least about 7 microns, an additional abrasive may beused, selected from the group consisting of pumice, perlite,precipitated silica, calcium carbonate, rice hull silica, silica gels,aluminas, phosphates including orthophosphates, polymetaphosphates,pyrophosphates, other inorganic particulates, and mixtures thereof. Inembodiments with the larger particle size, the fused silica may be fromabout 1% to about 10%, by weight of the composition. Some embodimentsmay be essentially free of surfactant, fluoride, or any oral careactive. Some embodiments may have a flavoring agent. Some embodimentsare methods of cleaning and polishing dental enamel by comprising anoral care composition wherein the median particle size is at least about7 microns and the composition has a PCR of at least about 100.

Fused silica may be made by melting silica (quartz or sand) at 2000° C.After cooling into ingots or pellets, the material is milled. Millingtechniques vary, but some examples include jet milling, hammer milling,or ball milling. Ball milling may result in more rounded edges to theparticles, while jet milling may result in more sharp or angular edges.Fused silica may be made by the process disclosed in U.S. Pat. No.5,004,488, Mehrotra and Barker, 1991. Fused silica may also be made froma silicon-rich chemical precursor usually using a continuous flamehydrolysis process that involves chemical gasification of silicon,oxidation of this gas to silicon dioxide, and thermal fusion of theresulting dust. This process can produce spherical fused silica, but canbe more expensive. While the making of precipitated silica is a chemicalprocess, the making of fused silica is a natural process. The productionof fused silica produces less waste and offers better sustainabilitybenefits.

In some embodiments of the present invention, there may be multipletypes of fused silica. For example, fused silica may be made by meltingthe silica at even higher temperatures, such as 4000° C. Such fusedsilicas may have a different particle size or surface morphology, butstill maintain the benefits discussed above, including low reactivity,due to the relatively low surface hydroxyl concentration and/or low BETspecific surface area.

Precipitated, or hydrated, silicas are made by dissolving silica (sand)using sodium hydroxide and precipitating by adding sulfuric acid. Afterwashing and drying, the material is then milled. Such precipitatedsilicas may be made by the process disclosed in U.S. Pat. No. 6,740,311,White, 2004. Precipitated and other silicas are described in more detailin the Handbook of Porous Solids, edited by Ferdi Schuth, Kenneth S. W.Sing and Jens Weitkamp, chapter 4.7.1.1.1, called Formation of SilicaSols, Gels, and Powders, and in Cosmetic Properties and Structure ofFine-Particle Synthetic Precipitated Silicas, S. K. Wason, Journal ofSoc. Cosmetic Chem., vol. 29, (1978), pp 497-521.

The fused silicas of the present invention may be used alone or withother abrasives. A composition may comprise more than one type of fusedsilica. One type of abrasive that may be used with fused silica is aprecipitated silica. The total abrasive in the compositions describedherein is generally present at a level of from about 5% to about 70%, byweight of the composition. Preferably, dentifrice compositions containfrom about 5% to about 50% of total abrasive, by weight of thecomposition. For combinations of fused silica with precipitated silicas,the fused silica may be from about 1% to about 99%, by weight of thetotal abrasive. The precipitated silica or silicas may be from about 1%to about 99% by weight of the total abrasive. In some embodiments, smallamounts of fused silica may be used, from about 1% to about 10%, or fromabout 2% to about 5%.

The fused silica may be used in combination with inorganic particulatesthat have been treated with non-ionic surfactants such as ethoxylatedand non-ethoxylated fatty alcohols, acid and esters. One example of suchnon-ionic surfactant is PEG 40 hydrogenated Castor oil. In general, theoral care compositions of the present invention may be used withadditional abrasive material, such as one or more selected from thegroup consisting of precipitated silica, calcium carbonate, rice hullsilica, silica gels, aluminums, aluminum silicates, phosphates includingorthophosphates, polymetaphosphates, pyrophosphates, other inorganicparticulates, dicalcium phosphate dihydrate, calcium phosphate, perlite,pumice, calcium pyrophosphate, nanodiamonds, surface treated andde-hydrated precipitated silica, and mixtures thereof.

In some embodiments, the ratio of other abrasive to fused silica isgreater than about 2 to 1, in some embodiments, greater than about 10to 1. In some embodiments, the ratio is about 1 to 1. In someembodiments, the amount of fused silica, by weight of the composition,is from about 1% to about 10%. In some embodiments, the amount of fusedsilica, by weight of the abrasive combination, is from about 2% to about25%. In one embodiment, the other abrasive is calcium carbonate. In someembodiments, the amount of calcium carbonate, by weight of thecomposition, is from about 20% to about 60%. In some embodiments, theamount of calcium carbonate, by weight of the composition, is from about20% to about 60%. In another embodiment, an additional abrasive maycomprise at least one precipitated silica. The precipitated silicaabrasive may comprise from about 5% to about 40%, by weight of thecombination. The amount of fused silica in the abrasive combination maycomprise from about 1% to about 10%, by weight of the composition. Insome embodiments, the composition comprising an abrasive combination mayhave a PCR of at least about 80, about 100, or about 120, or an RDA ofless than about 150 or less than about 200.

To further increase cation availability in compositions, the fusedsilicas of the present invention may be used in combination with treatedprecipitated silicas, such as surface-modified precipitated silica,dehydrated precipitated silica, or precipitated silicas with reducedporosity, reduced surface hydroxyl groups, or small surface areas thathave better cation compatibility vs. regular precipitated silicas. Butit is emphasized that these particular precipitated silicas aresurface-treated in an attempt to reduce surface hydroxyls and to improveproperties such as low porosity or cationic compatibility, but that theywould still be considered precipitated silicas. (See, for example, U.S.Pat. No. 7,255,852, U.S. Pat. No. 7,438,895, WO 9323007, and WO9406868.) That is, they are silicas produced by a wet process. Water isadded during the manufacturing process and then later removed. Thatremains true even for a precipitated silica that may be heated to veryhigh temperatures in an attempt to remove hydroxyl groups. In contrast,fused silica, although it could be, does not need to be surface-treatedor treated at all. Fused silica is manufactured without any water, butby heating only. This heating process can more effectively reducesurface hydroxyls than most precipitated processes can.

Other abrasive polishing materials may include silica gels, rice hullsilica, aluminas, phosphates including orthophosphates,polymetaphosphates, and pyrophosphates, and mixtures thereof. Specificexamples include dicalcium orthophosphate dihydrate, calciumpyrophosphate, tricalcium phosphate, calcium polymetaphosphate,insoluble sodium polymetaphosphate, hydrated alumina, beta calciumpyrophosphate, calcium carbonate, and resinous abrasive materials suchas particulate condensation products of urea and formaldehyde, andothers such as disclosed by Cooley et al in U.S. Pat. No. 3,070,510,issued Dec. 25, 1962.

The abrasive can be precipitated silica or silica gels such as thesilica xerogels described in Pader et al., U.S. Pat. No. 3,538,230,issued Mar. 2, 1970, and DiGiulio, U.S. Pat. No. 3,862,307, issued Jan.21, 1975. Examples are the silica xerogels marketed under the trade name“Syloid” by the W.R. Grace & Company, Davison Chemical Division. Alsothere are the precipitated silica materials such as those marketed bythe J. M. Huber Corporation under the trade name, “Zeodent”,particularly the silicas carrying the designation “Zeodent 109” (Z-109)and “Zeodent 119” (Z-119). Other precipitated silicas commerciallyavailable and comparable to Z-109 and Z-119 include, for example,TIXOSIL 63, TIXOSIL 73, AND TIXOSIL 103, all made by Rhodia, Hubersilicas Z-103, Z-113, and Z-124, OSC DA, made by OSC in Taiwan, andABSIL-200 and ABSIL-HC, made by Madhu Silica. Of these commerciallyavailable precipitated silicas, TIXOSIL 73 is the most similar to Z-119.The present precipitated silica abrasives may be used in combinationwith fused silica and other abrasives.

The types of precipitated silica dental abrasives that may be mixed withthe fused silica of the present invention are described in more detailin Wason, U.S. Pat. No. 4,340,583, issued Jul. 29, 1982. Precipitatedsilica abrasives are also described in Rice, U.S. Pat. Nos. 5,589,160;5,603,920; 5,651,958; 5,658,553; and 5,716,601.

One suitable type of fused silica is TECO-SIL 44CSS, which is availablefrom C-E Minerals Products. Also available from C-E Minerals Productsare fused silicas designated as A TECO-SIL 44C, TECO-SIL T10, ANDTECOSPERE A. Other suitable fused silicas include R61000, available fromJiangsu Kaida Silica and SPHERON N-2000R and SPHERON P1500, availablefrom JGC, Japanese Glass Company. Others include RST 2500, RG 1500, andRG 5, available from Lianyungang Ristar Electronic Materials, SO-05 andS0-C4, available from Adamatech, FUSEREX AS-1, available from Tatsumori,FS 30 and FS-2DC, available from Denki Kagaku Kogyou, MIN-SIL 325F,available from Minco, and SUNSIL-130NP available from Sunjin, and afused silica from Shin-Etsu.

The CAS# for some types of fused silica is 60676-86-0. The CAS# forhydrated silica is 7631-86-9. The INCI name for fused silica is “fusedsilica”, while the INCI name for precipitated silicas is “hydratedsilica”. The silicas of the present invention do not include silicates,and the fused silicas of the present invention do not include fusedsilicates.

Due to precipitated silica's interaction with other formulationcomponents, precipitated silica can affect the rheology of a compositionover time. Fused silica, however, due to its lack of interaction withother formulation components, has little impact on rheology. This meansthat oral care compositions formulated with fused silica are more stableover time, which, among other things, can allow for better cleaning andbetter predictability. Thus, in some embodiments, structuring orthickening agents, combinations and amounts, may be very different fromthose of traditional dentifrices. Because the lack of thickeningprovided by fused silica, a gel network composition may be desired toaid in structuring the oral care composition.

Gel Networks

A gel network will be used in the oral composition. The gel network canbe used to structure the oral composition or to aid in delivering anactive, flavor, or other reactive material. The gel network may be usedto structure, meaning to thicken or provide the desired rheology, forthe fused silica oral compositions by itself or in combination withanother thickener or structuring agent. A gel network composition has arheology that may be advantageous for fused silica as fused silica ismore dense than some other abrasives or materials used in oralcompositions. Because the fused silica is heavier or more dense, it mayfall or drop out of the composition or solution more easily than otherless dense materials. This may be when the composition is diluted withwater. For example, when a dentifrice is used for brushing, it isdiluted by water when in the mouth. The dilution viscosity or rheologyfor a dentifrice containing a gel network aiding in structuring thedentifrice may be higher than dentifrices structured with polymeric ormore typical thickening materials. A higher dilution viscosity orrheology is beneficial in keeping the fused silica suspended andallowing the fused silica to participate more fully in the cleaningprocess. If a material, such as the abrasive, is not suspended ormaintained in the composition once diluted, the cleaning efficacy, suchas pellicle cleaning ratio, may decrease. Additionally, as more of theabrasive or fused silica is suspended, the oral composition may containless abrasives overall since more of the abrasive is able to participatein the cleaning. FIG. 13 shows PCR and RDA data for compositionsstructured by gel networks compared to compositions which are notstructured by gel networks but thickened with typical polymeric binders.As shown, the PCR score increases from 92.5 to 127.56 and from 95.44 to121.04 when a gel network is used in a formula containing 15% fusedsilica. This PCR increase for gel network structured compositions ofgreater than about 10%, about 15%, about 20%, or about 25% compared topolymer thickened compositions may be due to the gel networks ability tosuspend more of the fused silica during cleaning. While the cleaningscores increase, the abrasion remains in acceptable ranges.

A gel network may also be preferred to structure an oral compositioncomprising fused silica because of the gel networks ability to not reactwith other materials. Particularly, the gel networks do not negativelyaffect the stability of hydrogen peroxide or other oxidizing agents.Also, the gel networks do not negatively affect the stability of otheractive materials such as stannous, fluoride, essential oils, otherflavor components, or combinations thereof.

The viscosity of the composition at the time it is made may remain theviscosity of the composition, or, stated differently, the compositionmay have a stable viscosity. For the viscosity to be considered stable,typically the viscosity changes no more than about 5% after 30 days. Insome embodiments, the viscosity of the composition does not change bymore than about 5% after about 30 days, by more than about 10% afterabout 30 days, by more than about 20% after about 30 days, or by morethan about 50% after about 90 days. Because the problem of unstableviscosity over time is more pronounced in formulations with low wateramounts, in some embodiments, the compositions of the present inventionmay contain less than about 20% total water, or less than about 10%total water. Fused silica and gel networks can aid in the formulation ofstable viscosity for oral compositions. Because the fused silica doesnot absorb as much water as other abrasives, it will not change therheology over time as significantly. Gel networks are also know to bevery stable once the network is formed and there is not a significantchange or build in the viscosity over time.

The oral compositions of the present invention may comprise a dispersedgel network. As used herein, the term “gel network” refers to a lamellaror vesicular solid crystalline phase which comprises at least one fattyamphiphile, at least one surfactant, and a solvent. The lamellar orvesicular phase comprises bi-layers made up of a first layer comprisingthe fatty amphiphile and the secondary surfactant and alternating with asecond layer comprising the solvent. For the lamellar crystalline phaseto form, the fatty amphiphile and secondary surfactant must be dispersedwithin the solvent. The term “solid crystalline”, as used herein, refersto the structure of the lamellar or vesicular phase which forms at atemperature below the chain melt temperature of the layer in the gelnetwork comprising the one or more fatty amphiphiles. The gel networkssuitable for use in the present invention are described in more detailin US 2008/0081023A1 which describes the materials, methods of making,and uses of the gel networks. Additionally, US 2009/0246151A1 alsodescribes gel networks and method of making the compositions containinggel networks.

The gel network in the oral composition can be used to structure theoral composition. The structuring provided by the gel network providesthe desired rheology or viscosity by thickening the oral composition.The structuring can be done without the need for polymeric thickeningagents, however, polymeric thickeners or other agents could be used inaddition to the gel network to structure the oral composition. Becausethe fused silica does not provide any or as much thickening as a typicalprecipitated silica, the thickening of the oral composition may benefitmore from a gel network used to structure the oral composition. Thesmall or no effect that the fused silica has the viscosity or thickeningof the oral composition also may provide the benefit of being able toformulate an oral composition with a gel network or other thickeningsystem and then being able to add as much fused silica as desiredwithout needing to readjust the level of thickening as would be requiredif the amount of precipitated silica was adjusted.

The gel network component of the present invention comprises at leastone fatty amphiphile. As used herein, “fatty amphiphile” refers to acompound having a hydrophobic tail group and a hydrophilic head groupwhich does not make the compound water soluble (immiscible), wherein thecompound also has a net neutral charge at the pH of the oralcomposition. The fatty amphiphile can be selected from the groupconsisting of fatty alcohols, alkoxylated fatty alcohols, fatty phenols,alkoxylated fatty phenols, fatty amides, alkyoxylated fatty amides,fatty amines, fatty alkylamidoalkylamines, fatty alkyoxyalted amines,fatty carbamates, fatty amine oxides, fatty acids, alkoxylated fattyacids, fatty diesters, fatty sorbitan esters, fatty sugar esters, methylglucoside esters, fatty glycol esters, mono, di- and tri-glycerides,polyglycerine fatty esters, alkyl glyceryl ethers, propylene glycolfatty acid esters, cholesterol, ceramides, fatty silicone waxes, fattyglucose amides, phospholipids, and combinations thereof. Suitable fattyamphiphiles include a combination of cetyl alcohol and stearyl alcohol.

The gel network also comprises a surfactant. One or more surfactants arecombined with the fatty amphiphile and oral carrier to form the gelnetwork of the present invention. The surfactant is typically watersoluble or miscible in the solvent or oral carrier. Suitable surfactantsinclude anionic, zwitterionic, amphoteric, cationic, and nonionicsurfactants. In one embodiment, anionic surfactants such as sodiumlauryl sulfate, are preferred. The surfactants may be a combination ofmore than one type of surfactants, such as an anionic and nonionicsurfactant. The gel network will likely also comprise solvents, such aswater or other suitable solvents. The solvent and the surfactanttogether contribute to the swelling of the fatty amphiphile. This, inturn, leads to the formation and the stability of the gel network. Inaddition to forming the gel network, the solvent can help to keep thedentifrice composition from hardening upon exposure to air and provide amoist feel in the mouth. The solvent, as used herein, refers to suitablesolvents which can be used in the place of or in combination with waterin the formation of the gel network of the present invention. Suitablesolvents for the present invention include water, edible polyhydricalcohols such as glycerin, diglycerin, triglycerin, sorbitol, xylitol,butylene glycol, erythritol, polyethylene glycol, propylene glycol, andcombinations thereof. Sorbitol, glycerin, water, and combinationsthereof are preferred solvents.

To form a gel network, the oral compositions may comprise fattyamphiphile in an amount from about 0.05% to about 30%, preferably fromabout 0.1% to about 20%, and more preferably from about 0.5% to about10%, by weight of the oral composition. The amount of fatty amphiphilewill be chosen based on the formation of the gel network and thecomposition of the oral formulation. For example, an oral compositioncontaining low amounts of water may require about 1% of a fattyamphiphile whereas an oral composition with higher amounts of water mayrequire 6% or more of a fatty amphiphile. The amount of surfactant andsolvent needed to form the gel network will also vary based on thematerials chosen, the function of the gel network, and amount of fattyamphiphile. The surfactant as part of gel network phase is typically inan amount from about 0.01% to about 15%, preferably from about 0.1% toabout 10%, and more preferably from about 0.3% to about 5%, by weight ofthe oral composition. In some embodiments, a diluted solution ofsurfactant in water is utilized. In one embodiment, the amount ofsurfactant is chosen based on the level of foaming desired in the oralcomposition and on the irritation caused by the surfactant. The solventmay be present in an amount suitable to achieve a gel network whencombined with fatty amphiphile and surfactant according to the presentinvention. The oral compositions may comprise at least about 0.05% of asolvent, by weight of the oral composition. The solvent may be presentin the oral composition in amount of from about 0.1% to about 99%, fromabout 0.5% to about 95%, and from about 1% to about 90%.

Orally-Acceptable Carrier

The carrier for the components of the present compositions may be anyorally-acceptable vehicle suitable for use in the oral cavity. Thecarrier may comprise suitable cosmetic and/or therapeutic actives. Suchactives include any material that is generally considered safe for usein the oral cavity and that provides changes to the overall appearanceand/or health of the oral cavity, including, but not limited to,anti-calculus agents, fluoride ion sources, stannous ion sources,whitening agents, anti-microbial, anti-malodor agents, anti-sensitivityagents, anti-erosion agents, anti-caries agents, anti-plaque agents,anti-inflammatory agents, nutrients, antioxidants, anti-viral agents,analgesic and anesthetic agents, H-2 antagonists, and mixtures thereof.When present, the level of cosmetic and/or therapeutic active in theoral care composition is, in one embodiment from about 0.001% to about90%, in another embodiment from about 0.01% to about 50%, and in anotherembodiment from about 0.1% to about 30%, by weight of the oral carecomposition.

Actives

One of the advantages of fused silica is its compatibility with othermaterials, particularly materials that are reactive and can looseefficacy such as actives. Because fused silica does not react as muchwith actives as compared to precipitated silica and other traditionalabrasives, less of the active can be used with the same efficacy. If theactive has any potential aesthetic negatives such an unpleasant orstrong taste, astringency, staining, or other negative aesthetic, thelower amount of active may be preferred. Additionally, the use of lessactive for the same or similar efficacy is a cost savings.Alternatively, if the same amount of active as used as traditionallyused, the active would have higher efficacy as more of it is availableto provide the benefit. Because the fused silica is slightly harder thantraditional abrasives such as precipitated silica, the fused silica mayalso remove more stain and/or clean better.

Actives include but are not limited to antibacterial actives, antiplaqueagents, anti-inflammatory agents, anticalculus agents, nutrients,antioxidants, analgesic agents, anesthetic agents, H-1 and H-2antagonists, antiviral actives, and combinations thereof A material oringredient may be categorized as more than one type of materials. Suchas an antioxidant may also be an antiplaque and antibacterial active.Examples of suitable actives include stannous fluoride, sodium fluoride,essential oils, mono alkyl phosphates, hydrogen peroxide, CPC, candcombinations thereof. The following is a non-limiting list of activesthat may be used in the present invention.

Fluoride Ion

The present invention may comprise a safe and effective amount of afluoride compound. The fluoride ion may be present in an amountsufficient to give a fluoride ion concentration in the composition at25° C., and/or in one embodiment can be used at levels of from about0.0025% to about 5.0% by weight, in another embodiment from about 0.005%to about 2.0% by weight, to provide anticaries effectiveness. A widevariety of fluoride ion-yielding materials can be employed as sources ofsoluble fluoride in the present compositions. Examples of suitablefluoride ion-yielding materials are disclosed in U.S. Pat. Nos.3,535,421, and 3,678,154. Representative fluoride ion sources include:stannous fluoride, sodium fluoride, potassium fluoride, amine fluoride,sodium monofluorophosphate, zinc fluoride, and many others. In oneembodiment the dentifrice composition comprises stannous fluoride orsodium fluoride, as well as mixtures thereof.

The pH of the oral composition may be from about 3 to about 8. The pH istypically measured as a slurry pH by methods known in the industry.Depending upon the actives used in the oral composition, a different pHmay be desired. For formulations containing fluoride, it may be desiredto have a pH slightly lower than typical dentifrices. Typical oralcompositions with precipitated silica and fluoride have a pH high enoughso that the fluoride in the formula does not form fluorosilicate andthen react with the hydroxyl groups on the precipitated silica. Becausethe number of hydroxyl groups on fused silica is lower than the numberof hydroxyl groups on precipitated silica, this is not an issue and thepH of the oral composition with fused silica can be lower.

Compositions containing fused silica and fluoride may have a pH of lessthan about 6.0 or less than about 5.5. The pH may be less than about 5.2or about 5.0. It may be desired to have a pH of from about 3.5 to about5 or from about 2.4 to about 4.8. The pH may be lower than 5.5 to allowhigher fluoride uptake because more fluoride is available. The low pHmay help to condition the tooth surface to accept more fluoride. Forformulations containing peroxide and fused silica, the pH may be lessthan 4.5 or less than 4.0. A formulation with peroxide and fused silicamay be from about 3.5 to about 4.0. For formulations comprising fusedsilica, stannous, and fluoride, it may be desired to have a pH of lessthan 5.0. A pH of less than 5.0 may enable more of the SnF3 stannousspecies to be formed.

Anticalculus Agent

Dentifrice compositions of the present invention may also comprise ananti-calculus agent, which in one embodiment may be present from about0.05% to about 50%, by weight of the oral care composition, in anotherembodiment is from about 0.05% to about 25%, and in another embodimentis from about 0.1% to about 15%. The anti-calculus agent may be selectedfrom the group consisting of polyphosphates (including pyrophosphates)and salts thereof; polyamino propane sulfonic acid (AMPS) and saltsthereof; polyolefin sulfonates and salts thereof; polyvinyl phosphatesand salts thereof; polyolefin phosphates and salts thereof;diphosphonates and salts thereof; phosphonoalkane carboxylic acid andsalts thereof; polyphosphonates and salts thereof; polyvinylphosphonates and salts thereof; polyolefin phosphonates and saltsthereof; polypeptides; and mixtures thereof; polycarboxylates and saltsthereof; carboxy-substituted polymers; and mixtures thereof. In oneembodiment, the polymeric polycarboxylates employed herein include thosedescribed in U.S. Pat. No. 5,032,386. An example of these polymers thatis commercially available is Gantrez from International SpecialtyProducts (ISP). In one embodiment, the salts are alkali metal orammonium salts. Polyphosphates are generally employed as their wholly orpartially neutralized water-soluble alkali metal salts such aspotassium, sodium, ammonium salts, and mixtures thereof. The inorganicpolyphosphate salts include alkali metal (e.g. sodium) tripolyphosphate,tetrapolyphosphate, dialkyl metal (e.g. disodium) diacid, trialkyl metal(e.g. trisodium) monoacid, potassium hydrogen phosphate, sodium hydrogenphosphate, and alkali metal (e.g. sodium) hexametaphosphate, andmixtures thereof. Polyphosphates larger than tetrapolyphosphate usuallyoccur as amorphous glassy materials. In one embodiment thepolyphosphates are those manufactured by FMC Corporation, which arecommercially known as Sodaphos (n≈6), Hexaphos (n≈13), and Glass H(n≈21, sodium hexametaphosphate), and mixtures thereof. Thepyrophosphate salts useful in the present invention include, alkalimetal pyrophosphates, di-, tri-, and mono-potassium or sodiumpyrophosphates, dialkali metal pyrophosphate salts, tetraalkali metalpyrophosphate salts, and mixtures thereof. In one embodiment thepyrophosphate salt is selected from the group consisting of trisodiumpyrophosphate, disodium dihydrogen pyrophosphate (Na₂H₂P₂O₇),dipotassium pyrophosphate, tetrasodium pyrophosphate (Na₄P₂O₇),tetrapotassium pyrophosphate (K₄P₂O₇), and mixtures thereof. Polyolefinsulfonates include those wherein the olefin group contains 2 or morecarbon atoms, and salts thereof. Polyolefin phosphonates include thosewherein the olefin group contains 2 or more carbon atoms.Polyvinylphosphonates include polyvinylphosphonic acid. Diphosphonatesand salts thereof include azocycloalkane-2,2-diphosphonic acids andsalts thereof, ions of azocycloalkane-2,2-diphosphonic acids and saltsthereof, azacyclohexane-2,2-diphosphonic acid,azacyclopentane-2,2-diphosphonic acid,N-methyl-azacyclopentane-2,3-diphosphonic acid, EHDP(ethane-1-hydroxy-1,1,-diphosphonic acid), AHP(azacycloheptane-2,2-diphosphonic acid),ethane-1-amino-1,1-diphosphonate, dichloromethane-diphosphonate, etc.Phosphonoalkane carboxylic acid or their alkali metal salts include PPTA(phosphonopropane tricarboxylic acid), PBTA(phosphonobutane-1,2,4-tricarboxylic acid), each as acid or alkali metalsalts. Polyolefin phosphates include those wherein the olefin groupcontains 2 or more carbon atoms. Polypeptides include polyaspartic andpolyglutamic acids.

Stannous Ion

The oral compositions of the present invention may include a stannousion source. As stated before, one of the advantages of fused silica isits compatibility with other materials, particularly materials that arereactive and can loose efficacy. Stannous ions are considered to bereactive so the use of stannous ions with a fused silica may have someimportant benefits. Because fused silica does not react as much withstannous as compared to precipitated silica and other traditionalabrasives, less of the stannous can be used with the same efficacy. Ithas been reported that stannous may have potential aesthetic negativessuch an unpleasant or strong taste, astringency, staining, or othernegative aesthetics that make the stannous containing oral compositionsless desirable for consumers. Therefore, using a lower amount ofstannous may be preferred. Additionally, the use of less stannous forthe same or similar efficacy is a cost savings. Alternatively, if thesame amount of stannous is used as traditionally used, the stannouswould have higher efficacy as more of it is available to provide thebenefit. Because the fused silica is slightly harder than traditionalabrasives such as precipitated silica, the fused silica may also removemore stain and/or clean better. It has also been discovered thatstannous containing formulations may increase the strength of the teeth.Therefore, formulations containing stannous may have lower RDA scoresthan comparable formulations not containing stannous. The lower RDAscores may provide for a better PCR to RDA ratio as the fused silica isa good cleaning abrasive and the stannous provides for stronger teeth.The synergy provided with the combination of fused silica and stannousprovides a highly efficacious, high cleaning formula for consumers.

The stannous ions may be provided from stannous fluoride and/or otherstannous salts. Stannous fluoride has been found to help in thereduction of gingivitis, plaque, sensitivity, erosion, and in improvedbreath benefits. The stannous ions provided in a dentifrice compositionwill provide efficacy to a subject using the dentifrice composition.Although efficacy could include benefits other than the reduction ingingivitis, efficacy is defined as a noticeable amount of reduction inin situ plaque metabolism. Formulations providing such efficacytypically include stannous levels provided by stannous fluoride and/orother stannous salts ranging from about 50 ppm to about 15,000 ppmstannous ions in the total composition. The stannous ion is present inan amount of from about 1,000 ppm to about 10,000 ppm, in one embodimentfrom about 3,000 ppm to about 7,500 ppm. Other stannous salts includeorganic stannous carboxylates, such as stannous acetate, stannousgluconate, stannous oxalate, stannous malonate, stannous citrate,stannous ethylene glycoxide, stannous formate, stannous sulfate,stannous lactate, stannous tartrate, and the like. Other stannous ionsources include, stannous halides such as stannous chlorides, stannousbromide, stannous iodide and stannous chloride dihydride. In oneembodiment the stannous ion source is stannous fluoride, in anotherembodiment stannous chloride dehydrate or trihydrate, or stannousgluconate. The combined stannous salts may be present in an amount offrom about 0.001% to about 11%, by weight of the oral care compositions.The stannous salts may, in one embodiment, be present in an amount offrom about 0.01% to about 7%, in another embodiment from about 0.1% toabout 5%, and in another embodiment from about 1.5% to about 3%, byweight of the oral care composition.

Whitening Agent

A whitening agent may be included as an active in the present dentifricecompositions. The actives suitable for whitening are selected from thegroup consisting of alkali metal and alkaline earth metal peroxides,metal chlorites, perborates inclusive of mono and tetrahydrates,perphosphates, percarbonates, peroxyacids, and persulfates, such asammonium, potassium, sodium and lithium persulfates, and combinationsthereof. Suitable peroxide compounds include hydrogen peroxide, ureaperoxide, calcium peroxide, carbamide peroxide, magnesium peroxide, zincperoxide, strontium peroxide and mixtures thereof. In one embodiment theperoxide compound is carbamide peroxide. Suitable metal chloritesinclude calcium chlorite, barium chlorite, magnesium chlorite, lithiumchlorite, sodium chlorite, and potassium chlorite. Additional whiteningactives may be hypochlorite and chlorine dioxide. In one embodiment thechlorite is sodium chlorite. In another embodiment the percarbonate issodium percarbonate. In one embodiment the persulfates are oxones. Thelevel of these substances is dependent on the available oxygen orchlorine, respectively, that the molecule is capable of providing tobleach the stain. In one embodiment the whitening agents may be presentat levels from about 0.01% to about 40%, in another embodiment fromabout 0.1% to about 20%, in another embodiment form about 0.5% to about10%, and in another embodiment from about 4% to about 7%, by weight ofthe oral care composition.

Oxidizing Agent

The compositions of the invention may contain an oxidizing agent, suchas a peroxide source. A peroxide source may comprise hydrogen peroxide,calcium peroxide, carbamide peroxide, or mixtures thereof. In someembodiments, the peroxide source is hydrogen peroxide. Other peroxideactives can include those that produce hydrogen peroxide when mixed withwater, such as percarbonates, e.g., sodium percarbonates. In certainembodiments, the peroxide source may be in the same phase as a stannousion source. In some embodiments, the composition comprises from about0.01% to about 20% of a peroxide source, in other embodiments from about0.1% to about 5%, in certain embodiments from about 0.2% to about 3%,and in another embodiment from about 0.3% to about 2.0% of a peroxidesource, by weight of the oral composition. The peroxide source may beprovided as free ions, salts, complexed, or encapsulated. It isdesirable that the peroxide in the composition is stable. The peroxidemay provide a reduction in staining, as measured by the Cycling StainTest, or other relevant methods.

In addition to the optional ingredients detailed below, certainthickeners and flavors offer better compatibility with oxidizing agentssuch as peroxide. For example, in some embodiments, preferred thickeningagents may be cross-linked polyvinylpyrrolidone, polyacrylates,alkylated polyacrylates, alkylated cross-linked polyacrylates, polymericalkylated polyethers, carbomers, alkylated carbomers, gel networks,non-ionic polymeric thickeners, SEPINOV EMT 10 (Seppic-hydroxyethylacrylate/sodium acryloldimethyltaurate copolymer), PURE THIX 1450, 1442,HH (PEG 180 laureth-50/TMMP or Polyether 1-Rockwood Specialties),Structure 2001 (Akzo-Acrylates/Steareth-20 Itaconate copolymer),STRUCTURE 3001 (Akzo-Acrylates/Ceteth-20 Itaconate copolymer), ACULYN 28(Dow Chemical/Rohm and Haas-Acrylates/Beheneth-25 MethacrylateCopolymer), GENOPUR 3500D (Clariant), ACULYN 33 (Dow Chemical/Rohm andHaas-Acrylates Copolymer), ACULYN 22 (Dow Chemical/Rohm andHaas-Acrylates/Steareth-20 Methacrylate Copolymer), ACULYN 46 (DowChemical/Rohm and Haas-PEG-150/Stearyl Alcohol/SMDI Copolymer), A500(crosslinked carboxymethylcellulose-Hercules), STRUCTURE XL(hydroxypropyl starch phosphate-National Starch), and mixtures thereof.

Other suitable thickening agents may include polymeric sulfonic acidssuch as AVC, AVS, BLV and HMB (Clariant, acryloyldimethyltauratepolymers, co-polymers and cross polymers), DIAFORMER (Clariant,amineoxide methacrylate copolymer), GENAPOL (Clariant, fatty alcoholpolyglycol ether and alkylated polyglycol ethoxylated fatty alcohol),fatty alcohols, ethoxylated fatty alcohols, high molecular weightnon-ionic surfactants such as BRIJ 721 (Croda), and mixtures thereof.

Suitable flavor systems particularly compatible with peroxide includethose discussed in US application 2007/0231278. In one embodiment, theflavor system comprises menthol in combination with at least onesecondary cooling agent along with selected traditional flavorcomponents that have been found to be relatively stable in the presenceof peroxide. By “stable” herein is meant that the flavor character orprofile does not significantly change or is consistent during the lifeof the product.

The present composition may comprise from about 0.04% to 1.5% totalcoolants (menthol+secondary coolant) with at least about 0.015% mentholby weight. Typically, the level of menthol in the final compositionranges from about 0.015% to about 1.0% and the level of secondarycoolant(s) ranges from about 0.01% to about 0.5%. Preferably, the levelof total coolants ranges from about 0.03% to about 0.6%.

Suitable secondary cooling agents or coolants to be used with mentholinclude a wide variety of materials such as carboxamides, ketals, diols,menthyl esters and mixtures thereof. Examples of secondary coolants inthe present compositions are the paramenthan carboxamide agents such asN-ethyl-p-menthan-3-carboxamide, known commercially as “WS-3”,N,2,3-trimethyl-2-isopropylbutanamide, known as “WS-23”, and others inthe series such as WS-5, WS-11, WS-14 and WS-30. Additional suitablecoolants include 3-1-menthoxypropane-1,2-diol known as TK-10manufactured by Takasago; menthone glycerol acetal known as MGA; menthylesters such as menthyl acetate, menthyl acetoacetate, menthyl lactateknown as Frescolat® supplied by Haarmann and Reimer, and monomenthylsuccinate under the tradename Physcool from V. Mane. The terms mentholand menthyl as used herein include dextro- and levorotatory isomers ofthese compounds and racemic mixtures thereof. TK-10 is described in U.S.Pat. No. 4,459,425, Amano et al., issued Jul. 10, 1984. WS-3 and otheragents are described in U.S. Pat. No. 4,136,163, Watson, et al., issuedJan. 23, 1979.

Traditional flavor components that have been found to be relativelystable in the presence of peroxide include methyl salicylate, ethylsalicylate, methyl cinnamate, ethyl cinnamate, butyl cinnamate, ethylbutyrate, ethyl acetate, methyl anthranilate, iso-amyl acetate, iso-amylbutyrate, allyl caproate, eugenol, eucalyptol, thymol, cinnamic alcohol,cinnamic aldehyde, octanol, octanal, decanol, decanal, phenylethylalcohol, benzyl alcohol, benzaldehyde, alpha-terpineol, linalool,limonene, citral, vanillin, ethyl vanillin, propenyl guaethol, maltol,ethyl maltol, heliotropin, anethole, dihydroanethole, carvone, oxanone,menthone, β-damascenone, ionone, gamma decalactone, gamma nonalactone,gamma undecalactone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone and mixturesthereof. Generally suitable flavoring agents are those containingstructural features and functional groups that are less prone tooxidation by peroxide. These include derivatives of flavor chemicalsthat are saturated or contain stable aromatic rings or ester groups.Also suitable are flavor chemicals that may undergo some oxidation ordegradation without resulting in a significant change in the flavorcharacter or profile. Flavoring agents are generally used in thecompositions at levels of from about 0.001% to about 5%, by weight ofthe composition.

In some embodiments, the pH of the composition may be from about 3.5 toabout 5.5, which can provide additional stability for the oxidizingagent. In some embodiments, the composition may further comprise astannous ion source. In some embodiments, the present invention mayprovide a method of reducing plaque, gingivitis, sensitivity, oralmalodor, erosion, cavities, calculus, and staining by administering to asubject's oral cavity a composition comprising a fused silica and aperoxide. In some embodiments, the present invention provides a methodof reducing plaque, gingivitis, sensitivity, oral malodor, erosion,cavities, calculus, and staining by administering to a subject's oralcavity first a composition not comprising a peroxide, and then acomposition comprising a fused silica and a peroxide. In someembodiments, the composition may be in a single phase. In someembodiments, the composition may comprise an oxidizing agent and one ormore of a fluoride ion source, zinc ion source, calcium ion source,phosphate ion source, potassium ion source, strontium ion source,aluminum ion source, magnesium ion source, or combinations thereof. Insome embodiments, the composition may comprise an oxidizing agent and achelant selected from the group consisting of polyphosphates,polycarboxylates, polyvinylpyrrolidone, polyvinyl alcohol, polymericpolyether, polymeric alkyl phosphate, copolymers of methyl vinyl etherand maleic anhydride, polyphosphonates and mixtures thereof. In someembodiments, the composition may comprise an oxidizing agent and an oralcare active selected from the group consisting of antibacterial agents,antiplaque agents, anti-inflammatory agents, anticaries agents,anticalculus agents, antierosion agents, antimalodor agents,antisensitivity agents, nutrients, analgesic agents, anesthetic agents,H-1 and H-2 antagonists, antiviral actives, and combinations thereof. Insome embodiments, the antibacterial agent may be selected from the groupconsisting of cetylpyridinium chloride, chlorhexiding, hexitidine,triclosan, metal ions, essential oils and mixtures thereof.

Antibacterial Agent

Antimicrobial agents may be included in the dentifrice compositions ofthe present invention. Such agents may include, but are not limited tocationic antibacterials, such as chlorhexidine, alexidine, hexetidine,benzalkonium chloride, domiphen bromide, cetylpyridinium chloride (CPC),tetradecylpyridinium chloride (TPC), N-tetradecyl-4-ethylpyridiniumchloride (TDEPC), octenidine, bisbiguanides, zinc or stannous ionagents, grapefruit extract, and mixtures thereof. Other antibacterialand antimicrobial agents include, but are not limited to:5-chloro-2-(2,4-dichlorophenoxy)-phenol, commonly referred to astriclosan; 8-hydroxyquinoline and its salts, copper II compounds,including, but not limited to, copper(II) chloride, copper(II) sulfate,copper(II) acetate, copper(II) fluoride and copper(II) hydroxide;phthalic acid and its salts including, but not limited to thosedisclosed in U.S. Pat. No. 4,994,262, including magnesium monopotassiumphthalate; sanguinarine; salicylanilide; iodine; sulfonamides;phenolics; delmopinol, octapinol, and other piperidino derivatives;niacin preparations; nystatin; apple extract; thyme oil; thymol;antibiotics such as augmentin, amoxicillin, tetracycline, doxycycline,minocycline, metronidazole, neomycin, kanamycin, cetylpyridiniumchloride, and clindamycin; analogs and salts of the above; methylsalicylate; hydrogen peroxide; metal salts of chlorite; pyrrolidoneethyl cocoyl arginate; lauroyl ethyl arginate monochlorohydrate; andmixtures of all of the above. In another embodiment, the compositioncomprises phenolic antimicrobial compounds and mixtures thereof.Antimicrobial components may be present from about 0.001% to about 20%by weight of the oral care composition. In another embodiment theantimicrobial agents generally comprise from about 0.1% to about 5% byweight of the oral care compositions of the present invention.

Other antimicrobial agents may be, but are not limited to, essentialoils. Essential oils are volatile aromatic oils which may be syntheticor may be derived from plants by distillation, expression or extraction,and which usually carry the odor or flavor of the plant from which theyare obtained. Useful essential oils may provide antiseptic activity.Some of these essential oils also act as flavoring agents. Usefulessential oils include but are not limited to citra, thymol, menthol,methyl salicylate (wintergreen oil), eucalyptol, carvacrol, camphor,anethole, carvone, eugenol, isoeugenol, limonene, osimen, n-decylalcohol, citronel, a-salpineol, methyl acetate, citronellyl acetate,methyl eugenol, cineol, linalool, ethyl linalaol, safrola vanillin,spearmint oil, peppermint oil, lemon oil, orange oil, sage oil, rosemaryoil, cinnamon oil, pimento oil, laurel oil, cedar leaf oil, gerianol,verbenone, anise oil, bay oil, benzaldehyde, bergamot oil, bitteralmond, chlorothymol, cinnamic aldehyde, citronella oil, clove oil, coaltar, eucalyptus oil, guaiacol, tropolone derivatives such as hinokitiol,avender oil, mustard oil, phenol, phenyl salicylate, pine oil, pineneedle oil, sassafras oil, spike lavender oil, storax, thyme oil, tolubalsam, terpentine oil, clove oil, and combinations thereof. In oneembodiment the essential oils are selected from thymol, methylsalicylate, eucalyptol, menthol and combinations thereof.

In one embodiment of the present invention, oral care compositions areprovided comprising a blend of naturally occurring flavor ingredients oressential oils (EO) containing such flavor ingredients, the blendexhibiting excellent antimicrobial activity and comprising at least twocomponents, a first component selected from acyclic or non-ringstructures such as citral, neral, geranial, geraniol and nerol and asecond component selected from ring-containing or cyclic structures suchas eucalyptol, eugenol and carvacrol. Essential oils may be used toprovide the above flavor ingredients including oils of lemongrass,citrus (orange, lemon, lime), citronella, geranium, rose, eucalyptus,oregano, bay and clove. However, it may be preferable that the flavoringredients are provided as individual or purified chemicals rather thansupplied in the composition by addition of natural oils or extracts asthese sources may contain other components that may be unstable withother components of the composition or may introduce flavor notes thatare incompatible with the desired flavor profile resulting in a lessacceptable product from an organoleptic standpoint. Highly preferred foruse herein are natural oils or extracts that have been purified orconcentrated to contain mainly the desired component(s).

Preferably, the blend comprises 3, 4, 5 or more of the above components.Greater synergy in terms of antimicrobial efficacy may be obtained themore different components are blended together as long as the blendcomprises at least one non-ring structure and one ring structure. Apreferred blend comprises at least two ring structures or at least twonon-ring structures. For example a blend comprising two non-ringstructures (neral and geranial from citral) and eugenol as the ringstructure is highly preferred for its efficacy against oral bacteria.Another preferred blend comprises three non-ring structures (geraniol,neral and geranial) and two ring structures (eugenol and eucalyptol).Examples of such blend is discussed in further detail in US publishedapplication 2008/0253976A1.

Other antibacterial agents may be basic amino acids and salts. Otherembodiments may comprise arginine.

Anti-Plaque Agent

The dentifrice compositions of the present invention may include ananti-plaque agent such as stannous salts, copper salts, strontium salts,magnesium salts, copolymers of carboxylated polymers such as Gantrez ora dimethicone copolyol. The dimethicone copolyol is selected from C12 toC20 alkyl dimethicone copolyols and mixtures thereof. In one embodimentthe dimethicone copolyol is cetyl dimethicone copolyol marketed underthe Trade Name Abil EM90. The dimethicone copolyol in one embodiment canbe present in a level of from about 0.001% to about 25%, in anotherembodiment from about 0.01% to about 5%, and in another embodiment fromabout 0.1% to about 1.5% by weight of the oral care composition.

Anti-Inflammatory Agent

Anti-inflammatory agents can also be present in the dentifricecompositions of the present invention. Such agents may include, but arenot limited to, non-steroidal anti-inflammatory (NSAID) agents oxicams,salicylates, propionic acids, acetic acids and fenamates. Such NSAIDsinclude but are not limited to ketorolac, flurbiprofen, ibuprofen,naproxen, indomethacin, diclofenac, etodolac, indomethacin, sulindac,tolmetin, ketoprofen, fenoprofen, piroxicam, nabumetone, aspirin,diflunisal, meclofenamate, mefenamic acid, oxyphenbutazone,phenylbutazone and acetaminophen. Use of NSAIDs such as ketorolac areclaimed in U.S. Pat. No. 5,626,838. Disclosed therein are methods ofpreventing and/or treating primary and reoccurring squamous cellcarcinoma of the oral cavity or oropharynx by topical administration tothe oral cavity or oropharynx of an effective amount of an NSAID.Suitable steroidal anti-inflammatory agents include corticosteroids,such as fluccinolone, and hydrocortisone.

Nutrients

Nutrients may improve the condition of the oral cavity and can beincluded in the dentifrice compositions of the present invention.Nutrients include minerals, vitamins, oral nutritional supplements,enteral nutritional supplements, and mixtures thereof. Useful mineralsinclude calcium, phosphorus, zinc, manganese, potassium and mixturesthereof. Vitamins can be included with minerals or used independently.Suitable vitamins include Vitamins C and D, thiamine, riboflavin,calcium pantothenate, niacin, folic acid, nicotinamide, pyridoxine,cyanocobalamin, para-aminobenzoic acid, bioflavonoids, and mixturesthereof. Oral nutritional supplements include amino acids, lipotropics,fish oil, and mixtures thereof. Amino acids include, but are not limitedto L-Tryptophan, L-Lysine, Methionine, Threonine, Levocarnitine orL-carnitine and mixtures thereof. Lipotropics include, but are notlimited to, choline, inositol, betaine, linoleic acid, linolenic acid,and mixtures thereof. Fish oil contains large amounts of Omega-3 (N-3)polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoicacid. Enteral nutritional supplements include, but are not limited to,protein products, glucose polymers, corn oil, safflower oil, mediumchain triglycerides. Minerals, vitamins, oral nutritional supplementsand enteral nutritional supplements are described in more detail in DrugFacts and Comparisons (loose leaf drug information service), WoltersKluer Company, St. Louis, Mo., ©1997, pps. 3-17 and 54-57.

Antioxidants

Antioxidants are generally recognized as useful in dentifricecompositions. Antioxidants are disclosed in texts such as Cadenas andPacker, The Handbook of Antioxidants, © 1996 by Marcel Dekker, Inc.Antioxidants useful in the present invention include, but are notlimited to, Vitamin E, ascorbic acid, Uric acid, carotenoids, Vitamin A,flavonoids and polyphenols, herbal antioxidants, melatonin,aminoindoles, lipoic acids and mixtures thereof.

Analgesic and Anesthetic Agents

Anti-pain or desensitizing agents can also be present in the dentifricecompositions of the present invention. Analgesics are agents thatrelieve pain by acting centrally to elevate pain threshold withoutdisturbing consciousness or altering other sensory modalities. Suchagents may include, but are not limited to: strontium chloride;potassium nitrate; sodium fluoride; sodium nitrate; acetanilide;phenacetin; acertophan; thiorphan; spiradoline; aspirin; codeine;thebaine; levorphenol; hydromorphone; oxymorphone; phenazocine;fentanyl; buprenorphine; butaphanol; nalbuphine; pentazocine; naturalherbs, such as gall nut; Asarum; Cubebin; Galanga; scutellaria;Liangmianzhen; and Baizhi. Anesthetic agents, or topical analgesics,such as acetaminophen, sodium salicylate, trolamine salicylate,lidocaine and benzocaine may also be present. These analgesic activesare described in detail in Kirk-Othmer, Encyclopedia of ChemicalTechnology, Fourth Edition, Volume 2, Wiley-Interscience Publishers(1992), pp. 729-737.

H-1 and H-2 Antagonists and Antiviral Actives

The present invention may also optionally comprise selective H-1 and H-2antagonists including compounds disclosed in U.S. Pat. No. 5,294,433.Antiviral actives useful in the present composition include any knowactives that are routinely use to treat viral infections. Suchanti-viral actives are disclosed in Drug Facts and Comparisons, WoltersKluer Company, ©1997, pp. 402(a)-407(z). Specific examples includeanti-viral actives disclosed in U.S. Pat. No. 5,747,070, issued May 5,1998. Said patent discloses the use of stannous salts to controlviruses. Stannous salts and other anti-viral actives are described indetail in Kirk & Othmer, Encyclopedia of Chemical Technology, ThirdEdition, Volume 23, Wiley-Interscience Publishers (1982), pp. 42-71. Thestannous salts that may be used in the present invention would includeorganic stannous carboxylates and inorganic stannous halides. Whilestannous fluoride may be used, it is typically used only in combinationwith another stannous halide or one or more stannous carboxylates oranother therapeutic agent.

Chelating Agent

The present compositions may optionally contain chelating agents, alsocalled chelants or sequestrants, many of which also have anticalculusactivity or tooth substantive activity. Use of chelating agents in oralcare products is advantageous for their ability to complex calcium suchas found in the cell walls of bacteria. Chelating agents can alsodisrupt plaque by removing calcium from the calcium bridges which helphold this biomass intact. Chelating agents also have the ability tocomplex with metallic ions and thus aid in preventing their adverseeffects on the stability or appearance of products. Chelation of ions,such as iron or copper, helps retard oxidative deterioration of finishedproducts.

In addition, chelants can in principle remove stains by binding to teethsurfaces thereby displacing color bodies or chromagens. The retention ofthese chelants can also prevent stains from accruing due to disruptionof binding sites of color bodies on tooth surfaces.

Therefore, chelants can aid in helping to mitigate stain and improvecleaning. A chelant may help to improve the cleaning as fused silica andabrasives clean in a mechanical mechanism while the chelant may help toprovide chemical cleaning. Because the fused silica is a good mechanicalcleaner, there may be more stain removed so a chelant may be desired tohold, suspend, or complex with the stain so it is not able to restainthe tooth surface. Additionally, the chelant may coat the surface of thetooth to help prevent new stain.

Chelants may be desired to be added to formulations containing cationicantibacterial agents. It may be desired to add chelants to stannouscontaining formulations. The chelant is able to help stabilize thestannous and keep a higher amount of the stannous bioavailable. Thechelant may be used in stannous formulations which have a pH above about4.0. In some formulations, the stannous may be stable without the needfor a chelant as the stannous is more stable with fused silica ascompared to precipitated silica.

Suitable chelating agents include soluble phosphate compounds, such asphytates and linear polyphosphates having two or more phosphate groups,including tripolyphosphate, tetrapolyphosphate and hexametaphosphate,among others. Preferred polyphosphates are those having the number ofphosphate groups n averaging from about 6 to about 21, such as thosecommercially known as Sodaphos (n≈6), Hexaphos (n≈13), and Glass H(n≈21). Other polyphosphorylated compounds may be used in addition to orinstead of the polyphosphate, in particular polyphosphorylated inositolcompounds such as phytic acid, myo-inositol pentakis(dihydrogenphosphate); myo-inositol tetrakis(dihydrogen phosphate), myo-inositoltrikis(dihydrogen phosphate), and an alkali metal, alkaline earth metalor ammonium salt thereof. Preferred herein is phytic acid, also known asmyo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) or inositolhexaphosphoric acid, and its alkali metal, alkaline earth metal orammonium salts. Herein, the term “phytate” includes phytic acid and itssalts as well as the other polyphosphorylated inositol compounds. Theamount of chelating agent in the compositions will depend on thechelating agent used and typically will be from at least about 0.1% toabout 20%, preferably from about 0.5% to about 10% and more preferablyfrom about 1.0% to about 7%.

Still other phosphate compounds that are useful herein for their abilityto bind, solubilize and transport calcium are the surface activeorganophosphate compounds described above useful as tooth substantiveagents including organic phosphate mono-, di- or triesters.

Other suitable agents with chelating properties for use in controllingplaque, calculus and stain include polyphosphonates described in U.S.Pat. No. 3,678,154 to Widder et al., U.S. Pat. No. 5,338,537 to White,Jr., and U.S. Pat. No. 5,451, to Zerby et al.; carbonyl diphosphonatesin U.S. Pat. No. 3,737,533 to Francis; acrylic acid polymer or copolymerin U.S. Pat. No. 4,847,070, Jul. 11, 1989 to Pyrz et al. and in U.S.Pat. No. 4,661,341, Apr. 28, 1987 to Benedict et al.; sodium alginate inU.S. Pat. No. 4,775,525, issued Oct. 4, 1988, to Pera; polyvinylpyrrolidone in GB 741,315, WO 99/12517 and U.S. Pat. No. 5,538,714 toPink et al.; and copolymers of vinyl pyrrolidone with carboxylates inU.S. Pat. No. 5,670,138 to Venema et al. and in JP Publication No.2000-0633250 to Lion Corporation.

Still other chelating agents suitable for use in the present inventionare the anionic polymeric polycarboxylates. Such materials are wellknown in the art, being employed in the form of their free acids orpartially or preferably fully neutralized water soluble alkali metal(e.g. potassium and preferably sodium) or ammonium salts. Examples are1:4 to 4:1 copolymers of maleic anhydride or acid with anotherpolymerizable ethylenically unsaturated monomer, preferably methyl vinylether (methoxyethylene) having a molecular weight (M.W.) of about 30,000to about 1,000,000. These copolymers are available for example asGantrez® AN 139 (M.W. 500,000), AN 119 (M.W. 250,000) and S-97Pharmaceutical Grade (M.W. 70,000), of GAF Chemicals Corporation.

Other operative polymeric polycarboxylates include the 1:1 copolymers ofmaleic anhydride with ethyl acrylate, hydroxyethyl methacrylate,N-vinyl-2-pyrrolidone, or ethylene, the latter being available forexample as Monsanto EMA No. 1103, M.W. 10,000 and EMA Grade 61, and 1:1copolymers of acrylic acid with methyl or hydroxyethyl methacrylate,methyl or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone.

Additional operative polymeric polycarboxylates are disclosed in U.S.Pat. No. 4,138,477, Feb. 6, 1979 to Gaffar and U.S. Pat. No. 4,183,914,Jan. 15, 1980 to Gaffar et al. and include copolymers of maleicanhydride with styrene, isobutylene or ethyl vinyl ether; polyacrylic,polyitaconic and polymaleic acids; and sulfoacrylic oligomers of M.W. aslow as 1,000 available as Uniroyal ND-2.

Other suitable chelants include polycarboxylic acids and salts thereofdescribed in U.S. Pat. Nos. 5,015,467 to Smitherman 5,849,271 and5,622,689 both to Lukacovic; such as tartaric acid, citric acid,gluconic acid, malic acid; succinic acid, disuccinic acid and saltsthereof, such as sodium or potassium gluconate and citrate; citricacid/alkali metal citrate combination; disodium tartrate; dipotassiumtartrate; sodium potassium tartrate; sodium hydrogen tartrate; potassiumhydrogen tartrate; acid or salt form of sodium tartrate monosuccinate,potassium tartrate disuccinate, and mixtures thereof. In someembodiments, there may be mixtures or combinations of chelating agents.

Tooth Substantive Agent

The present invention may include a tooth substantive agent. Forpurposes of this application, tooth substantive agents are included aschelants also. Suitable agents may be polymeric surface active agents(PMSA's), including polyelectrolytes, more specifically anionicpolymers. The PMSA's contain anionic groups, e.g., phosphate,phosphonate, carboxy, or mixtures thereof, and thus, have the capabilityto interact with cationic or positively charged entities. The “mineral”descriptor is intended to convey that the surface activity orsubstantivity of the polymer is toward mineral surfaces such as calciumphosphate minerals in teeth.

PMSA's are useful in the present compositions because of their manybenefits such as stain prevention. It is believed the PMSA's provide astain prevention benefit because of their reactivity or substantivity tomineral or tooth surfaces, resulting in desorption of portions ofundesirable adsorbed pellicle proteins, in particular those associatedwith binding color bodies that stain teeth, calculus development andattraction of undesirable microbial species. The retention of thesePMSA's on teeth can also prevent stains from accruing due to disruptionof binding sites of color bodies on tooth surfaces.

The ability of PMSA's to bind stain promoting ingredients of oral careproducts such as stannous ions and cationic antimicrobials is alsobelieved to be helpful. The PMSA will also provide tooth surfaceconditioning effects which produce desirable effects on surfacethermodynamic properties and surface film properties, which impartimproved clean feel aesthetics both during and most importantly,following rinsing or brushing. Many of these agents are also expected toprovide tartar control benefits when included in oral compositions,hence providing improvement in both the appearance of teeth and theirtactile impression to consumers.

The PMSA's include any agent which will have a strong affinity for thetooth surface, deposit a polymer layer or coating on the tooth surfaceand produce the desired surface modification effects. Suitable examplesof such polymers are polyelectrolytes such as condensed phosphorylatedpolymers; polyphosphonates; copolymers of phosphate- orphosphonate-containing monomers or polymers with other monomers such asethylenically unsaturated monomers and amino acids or with otherpolymers such as proteins, polypeptides, polysaccharides,poly(acrylate), poly(acrylamide), poly(methacrylate), poly(ethacrylate),poly(hydroxyalkylmethacrylate), poly(vinyl alcohol), poly(maleicanhydride), poly(maleate) poly(amide), poly(ethylene amine),poly(ethylene glycol), poly(propylene glycol), poly(vinyl acetate) andpoly(vinyl benzyl chloride); polycarboxylates and carboxy-substitutedpolymers; and mixtures thereof. Suitable polymeric mineral surfaceactive agents include the carboxy-substituted alcohol polymers describedin U.S. Pat. Nos. 5,292,501; 5,213,789, 5,093,170; 5,009,882; and4,939,284; all to Degenhardt et al. and the diphosphonate-derivatizedpolymers in U.S. Pat. No. 5,011,913 to Benedict et al; the syntheticanionic polymers including polyacrylates and copolymers of maleicanhydride or acid and methyl vinyl ether (e.g., Gantrez®), as described,for example, in U.S. Pat. No. 4,627,977, to Gaffar et al. A preferredpolymer is diphosphonate modified polyacrylic acid. Polymers withactivity must have sufficient surface binding propensity to desorbpellicle proteins and remain affixed to enamel surfaces. For toothsurfaces, polymers with end or side chain phosphate or phosphonatefunctions are preferred although other polymers with mineral bindingactivity may prove effective depending upon adsorption affinity.

Additional examples of suitable phosphonate containing polymeric mineralsurface active agents include the geminal diphosphonate polymersdisclosed as anticalculus agents in U.S. Pat. No. 4,877,603 toDegenhardt et al; phosphonate group containing copolymers disclosed inU.S. Pat. No. 4,749,758 to Dursch et al. and in GB 1,290,724 (bothassigned to Hoechst) suitable for use in detergent and cleaningcompositions; and the copolymers and cotelomers disclosed as useful forapplications including scale and corrosion inhibition, coatings, cementsand ion-exchange resins in U.S. Pat. No. 5,980,776 to Zakikhani et al.and U.S. Pat. No. 6,071,434 to Davis et al. Additional polymers includethe water-soluble copolymers of vinylphosphonic acid and acrylic acidand salts thereof disclosed in GB 1,290,724 wherein the copolymerscontain from about 10% to about 90% by weight vinylphosphonic acid andfrom about 90% to about 10% by weight acrylic acid, more particularlywherein the copolymers have a weight ratio of vinylphosphonic acid toacrylic acid of 70% vinylphosphonic acid to 30% acrylic acid; 50%vinylphosphonic acid to 50% acrylic acid; or 30% vinylphosphonic acid to70% acrylic acid. Other suitable polymers include the water solublepolymers disclosed by Zakikhani and Davis prepared by copolymerizingdiphosphonate or polyphosphonate monomers having one or more unsaturatedC═C bonds (e.g., vinylidene-1,1-diphosphonic acid and2-(hydroxyphosphinyl)ethylidene-1,1-diphosphonic acid), with at leastone further compound having unsaturated C═C bonds (e.g., acrylate andmethacrylate monomers). Suitable polymers include thediphosphonate/acrylate polymers supplied by Rhodia under the designationITC 1087 (Average MW 3000-60,000) and Polymer 1154 (Average MW6000-55,000).

A preferred PMSA will be stable with other components of the oral carecomposition such as ionic fluoride and metal ions. Also preferred arepolymers that have limited hydrolysis in high water contentformulations, thus permitting a simple single phase dentifrice ormouthrinse formulation. If the PMSA does not have these stabilityproperties, one option is a dual phase formulation with the polymericmineral surface active agent separated from the fluoride or otherincompatible component. Another option is to formulate non-aqueous,essentially non-aqueous or limited water compositions to minimizereaction between the PMSA and other components.

One preferred PMSA is a polyphosphate. A polyphosphate is generallyunderstood to consist of two or more phosphate molecules arrangedprimarily in a linear configuration, although some cyclic derivativesmay be present. Although pyrophosphates (n=2) are technicallypolyphosphates, the polyphosphates desired are those having around threeor more phosphate groups so that surface adsorption at effectiveconcentrations produces sufficient non-bound phosphate functions, whichenhance the anionic surface charge as well as hydrophilic character ofthe surfaces. The inorganic polyphosphate salts desired includetripolyphosphate, tetrapolyphosphate and hexametaphosphate, amongothers. Polyphosphates larger than tetrapolyphosphate usually occur asamorphous glassy materials. Preferred in the present compositions arethe linear polyphosphates having the formula:XO(XPO₃)_(n)Xwherein X is sodium, potassium or ammonium and n averages from about 3to about 125. Preferred polyphosphates are those having n averaging fromabout 6 to about 21, such as those commercially known as Sodaphos (n≈6),Hexaphos (n≈13), and Glass H (n≈21) and manufactured by FMC Corporationand Astaris. These polyphosphates may be used alone or in combination.Polyphosphates are susceptible to hydrolysis in high water formulationsat acid pH, particularly below pH 5. Thus it is preferred to uselonger-chain polyphosphates, in particular Glass H with an average chainlength of about 21. It is believed such longer-chain polyphosphates whenundergoing hydrolysis produce shorter-chain polyphosphates which arestill effective to deposit onto teeth and provide a stain preventivebenefit.

Also useful as tooth substantive agents are nonpolymeric phosphatecompounds, in particular polyphosphorylated inositol compounds such asphytic acid, myo-inositol pentakis(dihydrogen phosphate); myo-inositoltetrakis(dihydrogen phosphate), myo-inositol trikis(dihydrogenphosphate), and an alkali metal, alkaline earth metal or ammonium saltthereof. Preferred herein is phytic acid, also known as myo-inositol1,2,3,4,5,6-hexakis (dihydrogen phosphate) or inositol hexaphosphoricacid, and its alkali metal, alkaline earth metal or ammonium salts.Herein, the term “phytate” includes phytic acid and its salts as well asthe other polyphosphorylated inositol compounds.

Other surface active phosphate compounds useful as tooth substantiveagents include organophosphates such as phosphate mono-, di- ortriesters such as described in commonly assigned application publishedas US20080247973A1. Examples include mono-di- and tri-alkyl and alkyl(poly)alkoxy phosphates such as dodecyl phosphate, lauryl phosphate;laureth-1 phosphate; laureth-3 phosphate; laureth-9 phosphate;dilaureth-10 phosphate; trilaureth-4 phosphate; C12-18 PEG-9 phosphateand salts thereof. Many are commercially available from suppliersincluding Croda; Rhodia; Nikkol Chemical; Sunjin; Alzo; HuntsmanChemical; Clariant and Cognis. Some preferred agents are polymeric, forexample those containing repeating alkoxy groups as the polymericportion, in particular 3 or more ethoxy, propoxy isopropoxy or butoxygroups.

Additional suitable polymeric organophosphate agents include dextranphosphate, polyglucoside phosphate, alkyl polyglucoside phosphate,polyglyceryl phosphate, alkyl polyglyceryl phosphate, polyetherphosphates and alkoxylated polyol phosphates. Some specific examples arePEG phosphate, PPG phosphate, alkyl PPG phosphate, PEG/PPG phosphate,alkyl PEG/PPG phosphate, PEG/PPG/PEG phosphate, dipropylene glycolphosphate, PEG glyceryl phosphate, PBG (polybutylene glycol) phosphate,PEG cyclodextrin phosphate, PEG sorbitan phosphate, PEG alkyl sorbitanphosphate, and PEG methyl glucoside phosphate.

Additional suitable non-polymeric phosphates include alkyl monoglyceride phosphate, alkyl sorbitan phosphate, alkyl methyl glucosidephosphate, alkyl sucrose phosphates.

Other useful tooth substantive agents include siloxane polymersfunctionalized with carboxylic acid groups, such as disclosed indisclosed in U.S. Pat. Nos. 7,025,950 and 7,166,235 both assigned to TheProcter & Gamble Co. These polymers comprise a hydrophobic siloxanebackbone and pendant anionic moieties containing carboxy groups and havethe ability to deposit onto surfaces from aqueous-based formulations orfrom essentially non-aqueous based formulations, forming a substantiallyhydrophobic coating on the treated surface. The carboxy functionalizedsiloxane polymers are believed to attach themselves to polar surfacesand to form a coating thereon by electrostatic interaction, i.e.,complex formation between the pendant carboxy groups with calcium ionspresent in teeth. The carboxy groups thus serve to anchor the siloxanepolymer backbone onto a surface thereby modifying it to be hydrophobic,which then imparts a variety of end use benefits to that surface such asease of cleaning, stain removal and prevention, whitening, etc. Thecarboxy functionalized siloxane polymer further acts to enhancedeposition of active agents onto the surface and to improve retentionand efficacy of these actives on the treated surface.

Also useful as tooth substantive agents are water-soluble orwater-dispersible polymeric agents prepared by copolymerizing one or amixture of vinyl pyrrolidone (VP) monomers with one or a mixture ofalkenyl carboxylate (AC) monomers, specifically C2-C12 alkenyl esters ofsaturated straight- or branched-chain C1-C19 alkyl carboxylic acidsdescribed in commonly assigned U.S. Pat. No. 6,682,722. Examples includecopolymers of vinyl pyrrolidone with one or a mixture of vinyl acetate,vinyl propionate, or vinyl butyrate. Preferred polymers have an averagemolecular weight ranging from about 1,000 to about 1,000,000, preferablyfrom 10,000 to 200,000, even more preferably from 30,000 to 100,000.

The amount of tooth substantive agent will typically be from about 0.1%to about 35% by weight of the total oral composition. In dentifriceformulations, the amount is preferably from about 2% to about 30%, morepreferably from about 5% to about 25%, and most preferably from about 6%to about 20%. In mouthrinse compositions, the amount of toothsubstantive agent is preferably from about 0.1% to 5% and morepreferably from about 0.5% to about 3%.

Additional Actives

Additional actives suitable for use in the present invention mayinclude, but are not limited to, insulin, steroids, herbal and otherplant derived remedies. Additionally, anti-gingivitis or gum care agentsknown in the art may also be included. Components which impart a cleanfeel to the teeth may optionally be included. These components mayinclude, for example, baking soda or Glass-H. Also, it is recognizedthat in certain forms of therapy, combinations of these above-namedagents may be useful in order to obtain an optimal effect. Thus, forexample, an anti-microbial and an anti-inflammatory agent may becombined in a single dentifrice composition to provide combinedeffectiveness.

Optional agents to be used include such known materials as syntheticanionic polymers, including polyacrylates and copolymers of maleicanhydride or acid and methyl vinyl ether (e.g., Gantrez), as described,for example, in U.S. Pat. No. 4,627,977, as well as, e.g., polyaminopropoane sulfonic acid (AMPS), zinc citrate trihydrate, polyphosphates(e.g., tripolyphosphate; hexametaphosphate), diphosphonates (e.g., EHDP;AHP), polypeptides (such as polyaspartic and polyglutamic acids), andmixtures thereof. Additionally, the dentifrice composition can include apolymer carrier, such as those described in U.S. Pat. Nos. 6,682,722 and6,589,512 and U.S. application Ser. Nos. 10/424,640 and 10/430,617.

Other Optional Ingredients

Buffering Agents

The dentifrice compositions may contain a buffering agent. Bufferingagents, as used herein, refer to agents that can be used to adjust thepH of the dentifrice compositions to a range of about pH 3.0 to about pH10. The buffering agents include alkali metal hydroxides, ammoniumhydroxide, organic ammonium compounds, carbonates, sesquicarbonates,borates, silicates, phosphates, imidazole, and mixtures thereof.Specific buffering agents include monosodium phosphate, trisodiumphosphate, sodium benzoate, benzoic acid, sodium hydroxide, potassiumhydroxide, alkali metal carbonate salts, sodium carbonate, imidazole,pyrophosphate salts, sodium gluconate, lactic acid, sodium lactate,citric acid, and sodium citrate. Buffering agents are used at a level offrom about 0.1% to about 30%, preferably from about 0.1% to about 10%,and more preferably from about 0.3% to about 3%, by weight of thedentifrice compositions.

Coloring Agent

Coloring agents may also be added to the present composition. Thecoloring agent may be in the form of an aqueous solution, preferably 1%coloring agent in a solution of water. Pigments, pealing agents, fillerpowders, talc, mica, magnesium carbonate, calcium carbonate, bismuthoxychloride, zinc oxide, and other materials capable of creating avisual change to the dentifrice compositions may also be used. Colorsolutions and other agents generally comprise from about 0.01% to about5%, by weight of the composition. Titanium dioxide may also be added tothe present composition. Titanium dioxide is a white powder which addsopacity to the compositions. Titanium dioxide generally comprises fromabout 0.25% to about 5%, by weight of the composition.

Flavoring Agent

Suitable flavoring components include oil of wintergreen, clove bud oil,menthol, anethole, methyl salicylate, eucalyptol, cassia, 1-menthylacetate, sage, eugenol, parsley oil, oxanone, alpha-irisone, marjoram,lemon, orange, propenyl guaethol, cinnamon, vanillin, ethyl vanillin,heliotropine, 4-cis-heptenal, diacetyl, methyl-para-tert-butyl phenylacetate, cranberry, chocolate, green tea, and mixtures thereof. Theessential oils may also be included as flavoring agents and aredescribed above in the discussion of antibacterial agents. Coolants mayalso be part of the flavor composition. Coolants suitable for thepresent compositions include the paramenthan carboxyamide agents such asN-ethyl-p-menthan-3-carboxamide (known commercially as WS-3, WS-23,WS-5), MGA, TK-10, Physcool, and mixtures thereof. Salivating agents,warming agents, numbing agents, and other optional materials can be usedto deliver a signal while the oral composition is being used. Due to theinteractivity of precipitated silicas, flavor components may becometrapped or emulsified, in effect disappearing so as to not be perceivedby a user. In contrast, fused silica's lack of interactivity may impactthe amount of a flavor component that must be added to achieve anoticeable effect. In some embodiments, the amount of flavoring agentpresent, by weight of the composition, may be about 10%, about 20%, orabout 50% less than comparable precipitated silica formulations whileachieving the same flavor impact.

A flavor composition is generally used in the oral care compositions atlevels of from about 0.001% to about 5%, by weight of the oral carecomposition. The flavor composition will preferably be present in anamount of from about 0.01% to about 4%, more preferably from about 0.1%to about 3%, and more preferably from about 0.5% to about 2% by weight.

Similarly, coolants may not be absorbed as much in the presentcompositions, meaning that the coolants may last longer, or may be usedin lesser amounts. Essential oils also may be absorbed less so that lessmay be used to achieve the same effectiveness. The fused silica may notattach to the taste receptor like precipitated silica does, meaning thatthe taste receptor may be more accessible to the flavoring agent.

Other aesthetic benefits may be apparent to users, such as a clean mouthexperience and an increased perception of sweetness or coolness, forexample. The improved slick, clean mouthfeel may contribute to a lesserperception of dry mouth, and well as the improved cleaning of the fusedsilica may help remove layers of muscin and increase the perception ofmoisturization. Another consumer aesthetic benefit may be improvedrinsing out of the mouth of the oral composition, due to the inert fusedsilica particles not clumping, but remaining dispersed while the userbrushes. Yet another potential benefit is improved foaming Again,because the fused silica is less reactive than precipitated silica,surfactants are more available and improved foaming may result.

Some embodiments may comprise a TRPV1 activator, a transient receptorpotential vanilloid receptor 1 activator, which is a ligand-gated,non-selective cation channel preferentially expressed on small-diametersensory neurons and detects noxious as well as other substances. Byadding a TRPV1 activator to an oral care composition with an off tastingcomponent, the user of the composition may experience an improved tasteover an oral care composition without the TRPV1 activator. Thus, theTRPV1 activator works to off-set the bad taste associated with manycomponents used in oral care compositions. These activators may not onlyoff-set bad tastes, but may also reduce dryness perception, by limitingthe mouth's ability to perceive dryness. In one embodiment, the TRPV1activator comprises vanillyl butyl ether, zingerone, capsaicin,capsiate, shoagol, gingerol, piperine, or a combination thereof. In oneembodiment, a TRPV1 activator will be added in an amount of about0.0001% to about 0.25% by weight of the oral care composition.

Sweetener

Sweetening agents can be added to the compositions. These includesweeteners such as saccharin, dextrose, sucrose, lactose, xylitol,maltose, levulose, aspartame, sodium cyclamate, D-tryptophan,dihydrochalcones, acesulfame, sucralose, neotame, and mixtures thereof.Various coloring agents may also be incorporated in the presentinvention. Sweetening agents are generally used in oral compositions atlevels of from about 0.005% to about 5%, by weight of the composition.

Thickening Agents

Additional thickening agents, such as polymeric thickeners, may beutilized in addition to the gel network. Suitable thickening agents arecarboxyvinyl polymers, carrageenan, hydroxyethyl cellulose, laponite andwater soluble salts of cellulose ethers such as sodiumcarboxymethylcellulose and sodium carboxymethyl hydroxyethyl cellulose.Natural gums such as gum karaya, xanthan gum, gum arabic, and gumtragacanth can also be used. Colloidal magnesium aluminum silicate orfinely divided silica can be used as part of the thickening agent tofurther improve texture. Other thickeners may include alkylatedpolyacrylates, alkylated cross-linked polyacrylates, or gel networks.Thickening agents can include polymeric polyether compounds, e.g.,polyethylene or polypropylene oxide (M.W. 300 to 1,000,000), capped withalkyl or acyl groups containing 1 to about 18 carbon atoms.

A suitable class of thickening or gelling agents includes a class ofhomopolymers of acrylic acid crosslinked with an alkyl ether ofpentaerythritol or an alkyl ether of sucrose, or carbomers. Carbomersare commercially available from B.F. Goodrich as the Carbopol® series.Particularly the carbopols include Carbopol 934, 940, 941, 956, andmixtures thereof.

Copolymers of lactide and glycolide monomers, the copolymer having themolecular weight in the range of from about 1,000 to about 120,000(number average), are useful for delivery of actives into theperiodontal pockets or around the periodontal pockets as a “subgingivalgel carrier.” These polymers are described in U.S. Pat. Nos. 5,198,220;5,242,910; and 4,443,430.

Thus, in some embodiments, thickening agents, combinations and amounts,may be very different from those of traditional dentifrices. In thepresent invention, thickening agents may be used in an amount from about0% to about 15%, or from about 0.01% to about 10%, or in anotherembodiment from about 0.1% to about 5%, by weight of the total oralcomposition.

In some embodiments of the present invention, the composition maycomprise a thickening agent selected from natural and synthetic sources.In some embodiments, the thickening agent may be selected from the groupconsisting of clay, laponite, and mixtures thereof. In some embodiments,the composition may further comprise a thickening agent selected fromthe group consisting of carboxyvinyl polymers, carrageenan, hydroxyethylcellulose, water soluble salts of cellulose ethers such as sodiumcarboxymethylcellulose, cross-linked carboxymethylcellulose, sodiumhydroxyethyl cellulose, cross-linked starch, natural gums such as gumkaraya, xanthan gum, gum arabic, and gum tragacanth, magnesium aluminumsilicate, silica, alkylated polyacrylates, alkylated cross linkedpolyacrylates, and mixtures thereof.

Other possible thickeners include carbomers, hydrophobically modifiedcarbomers, carboxymethyl cellulose, cetyl/stearyl alcohol, sodiumalginate, gellan gum, acylated gellan gum, sodium hydroxypropyl starchphosphate, microcrystalline cellulose, micro fibrous cellulose,crosslinked polyvinyl pyrrolidone, cetyl hydroxyethyl cellulose,crosslinked sodium acryloyl methyl propane sulfonic acid and copolymers,and mixtures thereof.

Humectant

A humectant can help to keep the dentifrice composition from hardeningupon exposure to air and provide a moist feel in the mouth. A humectantor additional solvent may be added to the oral carrier phase. Suitablehumectants for the present invention include water, edible polyhydricalcohols such as glycerin, sorbitol, xylitol, butylene glycol,polyethylene glycol, propylene glycol, and combinations thereof.Sorbitol, glycerin, water, and combinations thereof are preferredhumectants. The humectant may be present in an amount of from about 0.1%to about 99%, from about 0.5% to about 95%, and from about 1% to about90%.

Surfactants

A surfactant may be added to the dentifrice composition. Surfactants,also commonly referred to as sudsing agents, may aid in the cleaning orfoaming of the dentifrice composition. Suitable surfactants are thosewhich are reasonably stable and foam throughout a wide pH range. Thesurfactant may be anionic, nonionic, amphoteric, zwitterionic, cationic,or mixtures thereof.

Examples of anionic surfactants useful herein include the water-solublesalts of alkyl sulfates having from 8 to 20 carbon atoms in the alkylradical (e.g., sodium alkyl sulfate) and the water-soluble salts ofsulfonated monoglycerides of fatty acids having from 8 to 20 carbonatoms. Sodium lauryl sulfate (SLS) and sodium coconut monoglyceridesulfonates are examples of anionic surfactants of this type. Examples ofother suitable anionic surfactants are sarcosinates, such as sodiumlauroyl sarcosinate, taurates, sodium lauryl sulfoacetate, sodiumlauroyl isethionate, sodium laureth carboxylate, and sodium dodecylbenzenesulfonate. Mixtures of anionic surfactants can also be employed.Many suitable anionic surfactants are disclosed by Agricola et al., U.S.Pat. No. 3,959,458, issued May 25, 1976. In some embodiments, the oralcare composition may comprise an anionic surfactant at a level of fromabout 0.025% to about 9%, from about 0.05% to about 5% in someembodiments, and from about 0.1% to about 1% in other embodiments.

Another suitable surfactant is one selected from the group consisting ofsarcosinate surfactants, isethionate surfactants and tauratesurfactants. Preferred for use herein are alkali metal or ammonium saltsof these surfactants, such as the sodium and potassium salts of thefollowing: lauroyl sarcosinate, myristoyl sarcosinate, palmitoylsarcosinate, stearoyl sarcosinate and oleoyl sarcosinate. Thesarcosinate surfactant may be present in the compositions of the presentinvention from about 0.1% to about 2.5%, or from about 0.5% to about 2%by weight of the total composition.

Cationic surfactants useful in the present invention include derivativesof aliphatic quaternary ammonium compounds having one long alkyl chaincontaining from about 8 to 18 carbon atoms such as lauryltrimethylammonium chloride; cetyl pyridinium chloride; cetyltrimethylammonium bromide;di-isobutylphenoxyethyl-dimethylbenzylammonium chloride; coconutalkyltrimethylammonium nitrite; cetyl pyridinium fluoride; etc.Preferred compounds are the quaternary ammonium fluorides described inU.S. Pat. No. 3,535,421, Oct. 20, 1970, to Briner et al., where saidquaternary ammonium fluorides have detergent properties. Certaincationic surfactants can also act as germicides in the compositionsdisclosed herein.

Nonionic surfactants that can be used in the compositions of the presentinvention include compounds produced by the condensation of alkyleneoxide groups (hydrophilic in nature) with an organic hydrophobiccompound which may be aliphatic or alkylaromatic in nature. Examples ofsuitable nonionic surfactants include the Pluronics, polyethylene oxidecondensates of alkyl phenols, products derived from the condensation ofethylene oxide with the reaction product of propylene oxide and ethylenediamine, ethylene oxide condensates of aliphatic alcohols, acids, andesters, long chain tertiary amine oxides, long chain tertiary phosphineoxides, long chain dialkyl sulfoxides and mixtures of such materials.

Zwitterionic synthetic surfactants useful in the present inventioninclude derivatives of aliphatic quaternary ammonium, phosphonium, andsulfonium compounds, in which the aliphatic radicals can be straightchain or branched, and wherein one of the aliphatic substituentscontains from about 8 to 18 carbon atoms and one contains an anionicwater-solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphateor phosphonate.

Suitable betaine surfactants are disclosed in U.S. Pat. No. 5,180,577 toPolefka et al., issued Jan. 19, 1993. Typical alkyl dimethyl betainesinclude decyl betaine or 2-(N-decyl-N,N-dimethylammonio) acetate, cocobetaine or 2-(N-coc-N,N-dimethyl ammonio) acetate, myristyl betaine,palmityl betaine, lauryl betaine, cetyl betaine, cetyl betaine, stearylbetaine, etc. The amidobetaines are exemplified by cocoamidoethylbetaine, cocoamidopropyl betaine, lauramidopropyl betaine and the like.The betaines of choice are preferably the cocoamidopropyl betaine and,more preferably, the lauramidopropyl betaine.

Precipitated silica tends to lessen the foaming of an oral composition.In contrast, fused silica, with its low reactivity, does not inhibitfoaming, or does not inhibit foaming to the degree of precipitatedsilica. The lack of interference with surfactant components can impactthe amount of surfactant used, which in turn may affect other variables.For example, if less surfactant is needed to achieve acceptable consumerfoaming, this may reduce irritancy (a known consumer negative of SLS),or could lower the composition pH, which could allow better fluorideuptake.

In some embodiments, polymeric mineral surface active agents are addedto mitigate negative aesthetics of these compounds. The polymericmineral surface active agents may be organo phosphate polymers, which insome embodiments are alkyl phosphate esters or salts thereof,ethoxylated alkyl phosphate esters and salts thereof, or mixtures ofalkyl phosphate esters or salts thereof. In some embodiments, thepolymeric mineral surface active agents may be polycarboxylates orpolyphosphates or co-polymers of polymeric carboxylates such as Gantrez.

In some embodiments, the composition may comprise a fused silica and beessentially free of SLS. Essentially free means that there is less thanabout 0.01%, by weight of the composition. In some embodiments, thecomposition may further comprise a surfactant, other than SLS, selectedfrom the group consisting of a nonionic surfactant, an anionicsurfactant, a cationic surfactant, an amphoteric surfactant, azwitterionic surfactant, and mixtures thereof. In some embodiments, thecomposition may further comprise a chelant. In some embodiments, thesurfactant may be a amphoteric surfactant, such as betaine, for example.In some embodiments, the composition may have a PCR of at least about80. In some embodiments, the surfactant may be at least about 50%available. In some embodiments, the composition has less than 3% of asurfactant, by weight of the composition. In some embodiments, thecomposition may further comprise a peroxide source and/or enzymes. Someembodiments may be a method of treating a dry mouth condition byadministering to subject's oral cavity an oral composition comprisingfused silica, wherein the composition is essentially free of sodiumlauryl sulfate.

Method of Use

The present invention also relates to methods for cleaning and polishingteeth. The method of use herein comprises contacting a subject's dentalenamel surfaces and oral mucosa with the oral compositions according tothe present invention. The method of treatment may be by brushing with adentifrice or rinsing with a dentifrice slurry or mouthrinse. Othermethods include contacting the topical oral gel, mouthspray, toothpaste,dentifrice, tooth gel, tooth powders, tablets, subgingival gel, foam,mouse, chewing gum, lipstick, sponge, floss, toothbrush, petrolatum gel,or denture product or other form with the subject's teeth and oralmucosa. Depending on the embodiment, the oral composition may be used asfrequently as a toothpaste, or may be used less often, for example,weekly, or used by a professional in the form of a prophy paste or otherintensive treatment.

Additional Data

FIGS. 7-13 provide more detailed data on the material properties offused silica, as well as its compatibility with other oral carecomposition components, and its cleaning ability.

FIGS. 7( a) and 7(b) are formula compositions and correspondingstannous, zinc, and fluoride compatibility data. FIG. 7( a) shows theoral care compositions, formula A comprising precipitated silicas, andformula B comprising fused silica. FIG. 7( b) shows the compatibilitydata for both formula A and B at 25° C. and at 40° C. after 2 weeks, 1month, and 2 months, given as % compatibility. The data in FIG. 7 showsthat the fused silica composition provides superior stability andcompatibility with stannous, zinc, and fluoride.

It may be desired to have oral compositions with zinc salts wherein thecomposition has a bioavailability of zinc of greater than about 82%,85%, 87, or 90% after two weeks of storage at 25° C. It may be desiredthat the bioavailability of 82%, 85%, 87% or 90% remain until before useby the consumer. Therefore, the bioavailability may be measured beforeuse. Before use can mean that the product has been made, packed, anddistributed to a store or consumer but before the consumer has used theproduct. Storage conditions and temperatures during this time wouldvary.

It may be desired to have oral compositions with fluoride ions whereinthe composition has a fluoride bioavailability of greater than about88%, 90%, 91%, 92%, 93%, or 94% after two weeks of storage at 25° C. Itmay also be desired that the fluoride bioavailability remain at greaterthan about 88%, 90%, 91%, 92%, 93%, or 94% before use. For someformulations, fluoride bioavailability may remain at greater than 95%before use.

It may be desired to have oral compositions with stannous salts whereinthe composition has a compatibility of stannous of greater than about60%, 65%, 70%, 75%, 80%, 85%, or 90% after two weeks of storage at 25°C. Also, it may be desired that the stannous compatibility remain atgreater than about 60%, 65%, 70%, 75%, 80%, 85%, or 90% before use. Itsome compositions, the stannous compatibility may be at least about 92%.For fused silica formulations with stannous, the stannous compatibilitywill typically be about 20% to about 50%, about 25% to about 45%, about30% to about 40% higher than formulations with comparable amounts ofprecipitated silica and stannous.

FIG. 8 shows the stannous compatibility as a function of load. Thegreater the amount of precipitated silica, the lower the amount of freeor bioavailable stannous. The table demonstrates that the stannous lossto precipitated silica (Z-119) is 0.0081 g/g of Z-119 (or 80 ppm/1%Z-119 load). In contrast, the stannous loss to fused silica is 0.001 g/gof TECOSIL 44CSS (or 10 ppm/1% TECOSIL 44CSS load). In some embodiments,depending upon the surface area, the stannous loss to fused silica isfrom about 5 to about 50 ppm/1% load of fused silica, from about 7 toabout 30 ppm/1% load of fused silica, from about 8 to about 20 ppm/1%load of fused silica, or from about 10 to about 15 ppm/1% load of fusedsilica.

FIGS. 9( a) and 9(b) are peroxide containing compositions andcompatibility data. FIG. 9( a) shows peroxide-containing compositionswith various precipitated and fused silicas. FIG. 9( b) shows theperoxide compatibility of the compositions, at 40° C., initially, after6 days, and after 13 days. The data shows superior peroxidecompatibility with the fused silicas over the precipitated silicas. Insome embodiments, the peroxide compatibility is at least about 50%, atleast about 60%, at least about 70%, at least about 80%, or at leastabout 85% after about 13 days at 40° C. Stated another way, in someembodiments, after about 13 days at 40° C., at least about 50%, 60%,70%, or 85% of the peroxide or oxidizing agent may remain.

Method for sample preparation is as follows: Transfer 18 g of peroxidegel base in a plastic container; mix thoroughly 2 g of silica withspatula; measure pH of the mixture; divide the mixture into two equalparts and place one part at 25° C. and the other at 40° C.; placesamples in stability chamber at 25° C. and 40° C. Sample analysis is asfollows: Take an initial sample for peroxide analysis; take out samplesfrom stability chambers at 5 and 12 days and allow to equilibrate for 1day; remove 0.2 g of samples from each mixture and place remainingsamples back in the stability chamber; perform peroxide analysis asfollows: weigh 0.2000 g (+/−0.0200 g) of the peroxide gel into a 250 mLplastic beaker; add stir bar and 100 ml of 0.04N H2SO4, cover withparafilm, stir for at least 10 minutes; add 25 mL 10% KI solution and 3drops of NH4-Molybdate and stir additional 3-20 minutes; analyze viaautotitration with 0.1N Na-Thiosulfate. Compatibility is defined as theperoxide percent after 13 days at 40° C. divided by the initial peroxidepercent, then multiplied by 100. It is known to those of ordinary skillin the art that a product placed at 40° C. represents an extended shelflife. That is, for example, one month at 40° C. would roughlyapproximate eight months at room temperature.

FIG. 10( a) shows formulas A-E that are oral care compositionscomprising fused silica and peroxide. FIG. 10( b) shows the change inbrightness (Δ L) of bovine enamel specimens after a given number ofbrush strokes for two of the compositions in FIG. 10( a) that have fusedsilica and peroxide, in comparison to a formula with fused silica butnot peroxide (formula F), and a formula with neither fused silica norperoxide (Crest Cavity Protection Toothpaste). The data demonstratesthat the combination of fused silica and peroxide delivers superiorcleaning and whitening. In some embodiments, the delta L may be greaterthan about 4.5 at 50 strokes, greater than about 6.0 at 100 strokes,greater than about 9.0 at 200 strokes, or greater than about 15.0 at 400strokes. In some embodiments, the delta L may be from about 50% to about100% greater than Crest Cavity Protection Toothpaste. The method is asfollows: Substrates of bovine enamel are mounted and stained perconventional PCR protocol described by G. K. Stookey, et al., J. DentalRes., 61, 1236-9, 1982. Groups of 6 chips are divided for each treatmentleg, with each group having approximately the same baseline L value. 1:3slurries of treatment paste are made and stained bovine enamelsubstrates are brushed for 50, 100, 200, and 400 strokes with acalibrated force of 150 grams exerted during brushing. After brushingwith each number of strokes the substrates are imaged and analyzed for Lvalues. Change in L values are calculated as follows:ΔL=L_(post-brush)−L_(pre-brush and compared statistically using LSD)

FIG. 11( a) shows dentifrice composition formulas comprisingprecipitated or fused silicas, and FIG. 11( b) shows correspondingconsumer perception data. The consumer perception test was performedamong nine subjects who brushed with each product twice and providedfeed back via written questionnaire to questions related to flavordisplay and mouth feel. The subjects were asked to provide feedbackabout their experience during use, immediately after use and 15 minutesafter using the product. As shown in FIG. 11( b), in general, thecompositions comprising fused silica offer superior flavor intensity,refreshment, slick tooth feel, and clean mouth, when compared toprecipitated silica used in formula A.

FIG. 12 shows additional example formulas of oral care compositionscomprising fused silica. The formulas include compositions comprising agel network, combinations of fused silica with precipitated silica andwith calcium carbonate, compositions that are free of SLS, andcompositions that may be used as a prophy paste or used on a non-dailybasis.

FIG. 13( a) shows sodium fluoride based compositions in which formulas Aand B comprise precipitated silicas with traditional thickeners,formulas C and D comprise fused silica with traditional thickeners, andformulas E and F comprise fused silica with a gel network. FIG. 13( b)is a table of RDA and PCR values for the sodium fluoride-basedcompositions of FIG. 13( a), showing that use of fused silica improvesthe cleaning ability of a composition, and that use of a gel networkimproves the cleaning ability of the composition even more, all whilestill having acceptable abrasivity. FIG. 13( c) shows stannous fluoridebased compositions in similar embodiments to FIG. 13( a). FIG. 13( d)shows the corresponding RDA values for the FIG. 13( c) compositions,indicating that the use of stannous may decrease abrasion, showing thepotential strengthening of teeth by stannous formulas.

NON-LIMITING EXAMPLES

The dentifrice compositions illustrated in the following examplesillustrate specific embodiments of the dentifrice compositions of thepresent invention, but are not intended to be limiting thereof. Othermodifications can be undertaken by the skilled artisan without departingfrom the spirit and scope of this invention.

Example I

A-D are typical oral compositions comprising fused silica. Formula Bshows a combination of fused and precipitated silicas, and formula D acombination of fused silica and calcium carbonate:

Ingredient A B C D Sodium Fluoride 0.24 0.24 — — SodiumMonofluorophosphate — — 1.13 1.13 Sorbitol 59.58 59.58 59.58 24.00Glycerin — — — — Silica (ZEODENT 119) — 15.00 — Silica (ZEODENT 109) — —— Fused Silica (TECO-SIL 44CSS) 15.00 5.00 15.00 10.00 Calcium carbonate— — — 30.00 Sodium Phosphate Tribasic 1.10 1.10 1.10 0.40 Flavor 0.810.81 0.81 1.00 Carboxymethylcellulose Sodium 0.75 0.75 0.75 1.30Carrageenan — — — — Xanthan Gum — — — — Titanium Dioxide 0.53 0.53 0.53— Sodium Phosphate, Monobasic 0.42 0.42 0.42 0.10 Carbomer 956 0.30 0.300.30 — Saccharin Sodium 0.13 0.13 0.13 0.20 FD&C Dyes 0.05 0.05 0.05 —Sodium Lauryl Sulfate 4.00 4.00 4.00 7.00 Water QS QS QS QS 100.00100.00 100.00 100.00

Example II

A-F are typical oral compositions comprising fused silica with cationicantimicrobials:

Ingredient A B C D E F Sodium Fluoride — — — — — 0.24 Stannous Fluoride0.45 0.45 0.45 0.45 0.45 — Stannous Chloride 1.16 1.16 1.16 — — — Sodiumgluconate 1.06 1.06 1.06 1.06 1.06 — Zinc Citrate 0.53 0.53 0.53 — — —Zinc Lactate — — — 2.50 2.50 2.00 Cetyl pyrinidium chloride — — — — —0.25 Sodium hexametaphosphate — — — 13.00 13.00 — PEG 300 — — — 7.007.00 7.00 Sodium triployphsophate — — 5.00 — — 5.00 Phytic acid 0.800.80 — — — — Sorbitol 38.07 38.07 38.07 — — 50.00 Glycerin — — — 55.3355.33 8.00 Silica (ZEODENT 119) — — — — 5.00 — Silica (ZEODENT 109) —7.50 5.00 — — — Fused Silica (TECO-SIL 44CSS) 15.00 7.50 10.00 15.0010.00 15.00 Flavor 1.20 1.20 1.20 1.00 1.00 1.00 CarboxymethylcelluloseSodium 1.30 1.30 1.30 — — 1.30 Carrageenan — 0.70 0.70 0.60 0.60 —Xanthan Gum — — — 0.25 0.25 0.25 Titanium Dioxide 0.50 0.50 0.50 — — —Saccharin Sodium 0.25 0.25 0.25 0.25 0.25 0.25 FD&C Dyes — — — 0.05 0.050.05 Sodium Lauryl Sulfate 7.50 7.50 7.50 3.50 3.50 3.50 Water QS QS QSQS QS QS 100.00 100.00 100.00 100.00 100.00 100.00

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, it will be obvious to those skilled in theart that various changes and modifications may be made without departingfrom the spirit and scope of the invention. It is therefore intended tocover in the appended claims all such changes and modifications that arewithin the scope of the invention.

1. An oral care composition comprising fused silica having a particlesize wherein D90 is less than about 50 microns and a gel network.
 2. Thecomposition of claim 1 wherein the gel network structures thecomposition.
 3. The composition of claim 1 wherein the gel network isformed by one or more fatty amphiphiles.
 4. The composition of claim 3wherein said fatty amphiphile is selected from the group consisting offatty alcohols, alkoxylated fatty alcohols, fatty phenols, alkoxylatedfatty phenols, fatty amides, alkyoxylated fatty amides, fatty amines,fatty alkylamidoalkylamines, fatty alkyoxyalted amines, fattycarbamates, fatty amine oxides, fatty acids, alkoxylated fatty acids,fatty diesters, fatty sorbitan esters, fatty sugar esters, methylglucoside esters, fatty glycol esters, mono, di- and tri-glycerides,polyglycerine fatty esters, alkyl glyceryl ethers, propylene glycolfatty acid esters, cholesterol, ceramides, fatty silicone waxes, fattyglucose amides, phospholipids, and combinations thereof.
 5. Thecomposition of claim 4, wherein said fatty amphiphile is a combinationof cetyl alcohol and stearyl alcohol.
 6. The composition of claim 1further comprising a swelling surfactant.
 7. The composition of claim 6wherein the swelling surfactant is selected from the group consisting ofanionic surfactants, amphoteric surfactants, zwitterionic surfactants,nonionic surfactants, cationic surfactants, and combinations thereof. 8.The composition of claim 7 wherein said swelling surfactant is sodiumlauryl sulfate.
 9. The composition of claim 2 wherein the composition isessentially free of polymeric thickening materials.
 10. The compositionof claim 2 wherein the composition further comprises polymericthickening materials.
 11. The composition of claim 1 further comprisinghydrogen peroxide.
 12. The composition of claim 1 further comprisingstannous.
 13. The composition of claim 1 further comprising a mono or dialkyl phosphate.
 14. The composition of claim 1 further comprising anessential oil.
 15. An oral care composition comprising fused silicahaving a particle size wherein D90 is less than about 50 microns, a gelnetwork, hydrogen peroxide, a mono or di alkyl phosphate, an essentialoil, and a fluoride source selected from stannous fluoride and sodiumfluoride.
 16. The composition of claim 1 wherein at least 25% of thefused silica particles are spherical.
 17. The composition of claim 15wherein at least 25% of the fused silica particles are spherical.